Posted tagged ‘arc’

Mechanical Engineering Seminar Topics List 4

September 10, 2011

38. SAAB
42. SKY BUS 3
52. VVTI
54. YOUR CAR 2020
56. DTH TV
57. EDGE
64. TPM

68. A Study Of a Displacement Amplifier
69. Optimal Design and Analysis Of Automotive Composite Drive Safety
70. 1st Types of Production
71. A case study of management…
72. A design theory based
73. A Fluid-Solid Interaction Model Of The Solid Phase Apiary in stressed silicon layers
74. A High -Torque Magneto-Theological fluid clutch
75. A Hypersonic Hybrid Vehicle
76. Abrasion Wear Characteristic Of Sand Cast
77. Abrasive water jet
78. Acoustic Emission Based Machining Tool Condition Monitoring – An Overview
79. Acoustic Emission Based Machining Tool Condition Monitoring – An Overview
80. Active Suspension System
81. Adaptive Cruise Control for Modern Automobile
83. Advance systems in two wheelers
84. Advances in automobiles (Hybrid Vehicles)
85. AGV for FMS
86. Air Bearing Next Generation Bearings
87. Air birthing Angina
88. Air car
89. Air powered car
90. Air suspension system and its…
91. Alternative abrasive to diamond
92. Alternative fuel
93. Amphibious Army Surveillance Vehicle
94. Artificial Intelligence
95. Artificial Intelligence Future Around Us
96. Artificial intelligence (Modeling air fuel ratio control)
97. Artificial Intelligence in Mechanical field
98. Artificial Intelligence-Present and Future
99. Assembly of Water Cooler
100. Atomic Battery
101. Auto Drilling With Geneva
102. Automated assembly system
103. Automated Guided Vehicles
104. Automatic braking system
105. Automatic Transmission System
106. Automation and Robotics
107. Automation of Foundry for Production quality
108. Automation of Ultrasonic Testing Procedures
109. Automobile AC by Utilizing Waste Heat & Gases
110. Automobile Ac By Utilizing Waste Heat & Gases Advance
111. Automobile Air Conditioning
112. Autonomously Generative CMM Part
113. Balance Of Tool Holder
114. Ball Piston Engine
115. Bike of the future- pneumatic bike
116. Bio diesel : A Fuel for the Future
117. Bio diesel From Jatropha
118. Biogas
119. Biomass as an Alternate Fuel for Diesel Engine
120. Biomass as an Alternate Fuel for Diesel Engine
121. Business Excellence Through Quality Circles
122. Business Process Analysis By BPR
123. Business Process Re-Engineering
124. CAD & CAE in Bio-Medical Field
125. Caged ball technology
126. Carbon Nano-tubes
127. carbon nanotubes (GCO)
128. Catalytic Converters
129. Centrifugal Pump
130. Ceramic Hybrid Ball Bearing
131. Challenges In Plasma Spray Assembly Of Nano particles To Near Net Shaped Bulk Nano structures
132. Chloro-fluro carbons
133. Cleaning of metal..
134. Clutch lining testing machine
136. Coating of Carbide Inserts
137. Combing Developments & Their Significance-Mech10
138. Combustion Control Using Optical Fiber
139. Combustion Stability in I.C. Engines
140. Common Rail Injection System
141. Comparison Of Experimental And Finite Element Results For Elastic Plastic Stress
142. Complex system development
143. Compressed Air Cars Technology
144. Computational Fluid Dynamics
145. Computer Aided Production Engineering (CAPE)
146. Computer Integrated Manufacturing-Building the Factory of Future
147. Concentrating Solar Power Energy from Mirrors
148. Concept of flying train
149. Concurrent Engineering
150. Condition Monitoring Of Bearings
151. Condition Monitoring Through Vibration Measurement
152. Consolidation Behavior Of Cu-Co-Fe Pre-Alloyed Powers
153. Constitutive Modeling of Shape Memory Alloy Using Neural Networks
154. Continuous process improvement
155. Control of Cure Distribution in Polymer Composite
156. Control of Cure Distribution in Polymer Composite Parts Made by Laminated Object Fabrication (LOF)
157. Control Systems In Automobiles
158. Convection in Porous Media
159. Cost Effective Safety Instrumented Systems
160. Crop Harvesting Machine
161. Cryogenic Automotive Propulsion Zero Emission Vehicle
162. Cryogenic Processing of Wear Control
163. Cryogenic Rocket Engine & Their Propellants
164. Cummins Diesel Fuel System
165. Design of Efficient Production
166. Design, Implementation, Utilization of FEM
167. Determination of Transmission Spectra Using Ultrasonic NDE
168. Development & Application. Of New Cutting Tool Materials
169. Development in arc welding process using robot
170. Development of an AGV Material Handling System in a Flexible Manufacturing Environment
171. Development of Coated Electrodes For Welding of HSLA Steels
172. Development of hexapod Walking Robot Mechanical Design
173. Development of high performance heat sink based on screen fin tech.
174. Development of Self Lubricating Sintered Steels for Terminological Applications
175. Development of Simple Driver-friendly Electric 4WD System
176. Development of the electrostatic clutch
177. Digital Manufacturing Using STEP-NC
178. Direct Injection Process
179. Distribution Side Management for Urban Electric Utilities in India
180. Dry Sliding Wear Studies On Hybrid MMC’S – A Taguchi Technique
181. Effect of catalytic coating
182. Analysis Of Dimensionless Number For Heat Transfer Enhancements In Rectangular Channels
183. Effect Of Preload On Stability And Performance Of a Two-Lobe Journal Bearing
184. Effect of Pressure On Arc Welding Process
185. Effect Of Stacking Sequence On Notch Strength In Laminates
186. Efficiency In Boring
187. Electronically Controlled Air Suspension System
188. Embedded Applications Design Using Real-Time
189. Energy Engineering Bio diesel
190. Energy Saving Opportunity And Pollution Control In Furnaces
191. Engine & String less car
192. Enterprise Resource Planning
193. Environmental Friendly Refrigeration
194. Ethanol-Future Fuel For Indian Vehicles
195. Exert Quarts In Microprocessor Applications
196. Experimental Analysis of Modified Machine Tools
197. Experimental Stress Analysis For Pipes
198. External Nodes In Finite Element Analysis
199. Failure Analysis Of Lap And Wavy-Lap Composite Bonded Joints
200. Finite Element Analysis Of Robotic Arm For Optimal Work Space Determination
201. Flexible manufacturing system
202. Flying train
203. Frication Welding Of Austenitic Stainless Steel and Optimization of Weld Quality
204. Fuel cell technology
205. Gas Hydrates
207. Genetic Algorithm Based Optimum Design Of Composite Drive Shaft
208. Geothermal Energy Utilization
209. Globalization
210. Grid Generation and Simulation Using CFD
211. Guided Missiles
212. H.C.C.I Engine
213. Heat pipe
214. By Forced Convection In Metal Foams
215. Heat transfer
217. Hexapod machine tool
218. High Performance Heat Sink Based on Screen-Fin Technology
219. Hologram
220. Homogeneous combustion in IC engine
221. Human transporter
222. Hybrid engine
223. Hybrid Synergy Drive
224. Hydraulic analysis of hydrostatic bearing of primary sodium pump of a fast breeder reactor
226. Hydrogen Car
227. hydrogen fuel cell
228. Hydro-Pneumatics
229. I-Mode
230. Improving service quality..
231. In view of the high commercial gains of a commercial place I
232. Independent Wheel Vehicle Suspension
233. Indian Manufacturing Scenario
234. Industrial Team Behavior and Management Tools
235. Innovation In Automobile Industries
236. Integrated web enabled information…
237. Integration of reinforced
238. Intelligent braking and vehicular..
239. JKJ
240. Job Scheduling Using Neural Network
241. Network Foe Rapid Manufacturing
243. Kaizen culture
244. KANBAN-AN Integrated JIT System
245. Laser Beam Delivery through Optical Fiber in Laser Machining
246. Laser Machining
247. Laser Micromachining
248. Laser shot preening
249. Latest trends in steering systems
250. Level measurement of bulk solids
251. LEVEL
253. Liquefied natural gas
254. LNG vehicles
255. Logistics In A Competitive Milieu
256. Machine Vision
257. Machine phase fullerene
258. Machining of Advanced Composites with Abrasive
259. machining technology for….doc
260. Machining technology of leaf spring
261. Magne-gas-The Fuel of Future
262. Magnetic Bearing
263. Magnetic Refrigeration
264. magnetic refrigeration
265. Managerial
266. Manufacturing Of Leaf Spring
267. Master Planning for College Campus
269. Materials of the Future
270. Materials of the Future
271. Mechanical seal
272. Mechanics of Composite Materials
273. Mechatronic
274. Mechatronic Strategies for Torque Control of Electric Powered Screwdrivers
275. Mechatronic Strategies for Torque Control of Electric Powered Screwdrivers
277. Mechanical Properties Of MMC’S- An Experimental Investigation
278. Medical Application of Nano tech.
279. MEMS
280. Metal deposition
281. Metal Matrix composites
282. Methanol Vehicles
283. Micro air vehicle
284. Micro electro mechanical system
285. Microcellular Foam Technology
286. Micro finishing of rollers in roller bearings
287. Minimum Quantity Lubrication
288. Mission of mars
289. Modeling and Optimization on of Electron Beam Wealing Process Using ANOVA
290. Motronic engine management
291. Multifunction control system for robotic fire detection
292. Nano technology
293. Nano technology Binding experiment with Biosensor
294. Nano technology For Cancer Therapy
295. Nano technology – It’s Small, Small, Small, Small World
296. Navigation
297. Near Net Shape Fabrications Via Vacuum Plasma Spray Forming
298. Near net shape memory..
299. Negative Supercharging
300. Non Destructive Testing Of Welds
301. Nuclear fuel
302. Nuclear Space Craft
303. Nuclei’s Next Generation
304. Ny-Tran – Alternative to V Belts
305. Optimizing centrifugal pump
306. Options & Accessories of Car
307. Packaging
308. Piston Ring
309. Pneumatic bike
310. Policies to overcome barriers to the spread of Bio energy technologies in India
311. Power Generation by Using Road Speed Breakers
312. Process steam generation…….
313. Processing and Tribo Behavior Of Nylon Clay Nano composites Under Abrasive Wear Mode
314. Product definition and Role of Aesthetics..
315. PTFE As Lubricant
316. PVD film method
317. Quality Function Deployment (QFD) for TQM
318. Quality in maintenance through TPM
319. Quality Function Deployment
320. Quasi turbine – Future Trends in automobile engine
321. Quieter fans for HVAC
322. Radiant Energy Welding Process
323. Rapid prototyping
324. Rapid Prototyping – Slicing Strategies
325. Rapid Prototyping – Slicing Strategies
326. Rapid prototyping technique based on 3d welding
327. Redesign of plant layout using travel chart technique (a case study)
328. Reduction of idle time through TPM
329. Reliability Redundancy Design-Using
330. Remote engine starting..
331. Renesis Rotary Engine
332. Renewable Energy Design Application In Water Cooler
333. Research On Modified Layers Of Material Surface For Cr Mov Cold Die
334. results of test on laser ignition in internal combustion engine
335. Return of two stroke engine
336. Reverse Engineering
337. Reverse Engineering in Mechanical parts
338. Risk Management
339. Robonaut
340. Robot-by-voice- Experiments on commanding an industrial robot using the human voice
341. Robotics
342. Robotics for Performing Surgical Operations
343. Rotary Engines
344. Safe Handling Of Hc
345. Scope of MEMS in Space
346. Scramjet
347. Scrubber tech.
348. Self Activated Single Use Switch
349. Self replicating system
350. Selling price decision support system for a job order based manufacturing unit
351. Server clustering
352. Set up for Small Scale Industry
353. SEZs World-Class Hubs For Exporters
354. Simulation of Fuel Injection System of System of A Diesel Engine
355. Six – Stroke hybrid engine final
356. Six sigma
357. Six sigma – a quality control tool in industry
358. Six sigma effective process improvement
359. Six Stroke Engine
360. Size Reduction of Window Air Conditioner
361. Size Reduction of Window Air Conditioner
362. Smart tire
363. SMED
364. Software based reengineering..
365. Soil compaction
366. Solar air conditioning
367. Solar aircraft
368. Solar Chimney Power Generation System
369. Solar Energy Conservation to Hydrogen
370. Solar Power Satellite
371. Space Craft Structure
372. Space Elevator
373. Space robotics
374. Space transportation system
375. Spring gauge
376. Sterling engine
377. Sterling engine for co-generation
378. Strategies for product
379. Studies on Phosphoric Irons for Concrete Reinforcement Applications
380. Supply Chain Management
381. Synthesis of Planar Mechanism with Variable Topology – Review
382. System Improvements through TQM
383. Technical development in car
384. Technology of 21st Century Nano Technology
385. The Challenge of Intelligent Systems
386. The Design Of Cellular Manufacturing Systems And Whole Business Simulation
387. The Effects of Precipitate Distributions on HSLA Grain Structure
388. The Gyro Machine
389. Thermal Conductivity Of Poros Material
390. Thermo-electric Refrigeration System
391. Thread Locking Device for Handling Thread at Flexible Endoscopy
392. Topic On Sng
393. Total Productive Maintenance (TPM)
394. Total Quality Management
395. TQM Implementation Learning form Indian Organizations
396. Transient Thermal Analysis of Railway
397. Tribological characteristics of cutting fluid groups
398. Tribology
399. Tribology of IC engine
400. Tribology of sealing
401. Tribometer
402. Tubeless Tyre Technology
403. Turbine Technology In Car
404. Types Of Bearing
405. Typre Pressure Monitoring System
406. Tyre Monitoring System
407. Ultrasonic Nondestructive Testing
408. Ultrasonic Phased Array For Defect Cartlization
409. Unmanned Aerial Vehicle Uavs
410. Vacuum Chuck
411. Value engineering
412. Variable Compression Ratio (VCR)
413. Variable Compression Ratio Engines
414. VCR
415. Vehicle Dynamics
416. Vehicular Emission Control
417. Vibration Analysis of Flywheel Using Finite Element Analysis
418. Virtual Manufacturing System
419. Virtual Reality Simulation
420. Vrb_Systems
421. Waste heat driven refrigeration and chilling systems.
422. Water Diesel Emulsion with High Injection Press
423. Water Diesel Emulsion with High Injection Press
424. Water as a fuel car
425. Water jet technology
426. What Is A Nuclear Reactor
427. When upgrading tool holders
428. Wind Energy Conversion System

Welding and Farming – The Two Go Hand-In-Hand

September 8, 2011


Welding and FarmingWelding and farming? They have more in common than you might think. In fact, one astute farmer recently noted, “you can’t run a farm without welding.” This farmer was absolutely correct — to keep equipment in working order for the critical seasons of planting and harvesting, welding and hardfacing during the off-season are musts. A good working knowledge of these processes also comes in handy when your equipment breaks down during off-hours and you need to quickly fix so you can continue your work.

In this article, we will introduce you to some of the key concepts in welding and hardfacing. When we refer to welding, we are talking about joining metal pieces together to build something. The weld is primarily for strength purposes. Hardfacing, on the other hand, is depositing (by welding with special hardfacing electrodes) wear- resistant surfaces on existing metal components which are under stress to extend their service life. Hardfacing is very commonly done to metal edges that scrape or crush other tough materials -like the blade on a road grader.

Welding and FarmingWe will discuss different applications, ways to identify metallurgy, basic welding procedures and safety. So often, the beginning or novice welder will not get the desired results and assume his welding machine or electrodes are not working properly. In many of these instances, though, the farmer did not take the necessary preparations before welding or has chosen the wrong process, parameters or consumables. In this article, we hope to educate you so that you will know what to use in a few applications and can get the best results. Realize that although a little welding knowledge could help you a lot, there is a lot to becoming a true welding expert, which would cover many books!

Welding Applications

Welding and FarmingFarmers constantly need to repair and modify machinery and equipment to suit their specific needs. This instant ability to alter steel gates, chutes, animal pens, and machinery is such a tremendous benefit to the farmer. Repairing a broken plow or combine in the field by welding it where it broke in minutes can literally save an entire crop. The needs of beef cattle can usually be taken care of with mild steel. Dairy cattle, and virtually their entire milk-handling system require stainless steel. Two similar appearing animals with very different welding needs. But both needing welding to succeed.

Hardfacing Applications

There are many different items that could potentially benefit from hardfacing on the farm. They can basically be put into three “wear” categories – abrasion, impact, and metal-to-metal. Abrasion is one of the most common wears you will see on a farm, in this category falls all earth engaging implements such as tractor buckets, blades, teeth, grain handling products and feed mixers. Under the impact heading you will find equipment used to pound and smash such as crusher hammers. Metal-to-metal refers to wear from steel parts rolling or sliding against each other. Metal-to-metal wear occurs on such items as crane wheels, pulleys, idlers on track-drives, gear teeth and shafts.

Although farmers use welding and hardfacing techniques to rebuild old, worn-out components, Lincoln recommends hardfacing many new components as well. By hardfacing something that is new, it may increase the overall life expectancy of that product.

Basic Metallurgy

Before you can weld or hardface, you first need to identify the parent metal. A good rule of thumb on the farm is that nothing is mild steel. Almost all implements are high strength steels (either high or low alloy) and many are higher carbon steels. But how do you tell the difference? There are a couple of tests that can help.

Welding and FarmingThe first is a magnetic test. If a magnet will stick to the implement then it is likely iron-based. A magnet that will not stick indicates probably a manganese or stainless product. Secondly, try the spark test. If you take a grinder to the item, do you get 30″ long, moderately large volume of yellow sparks with just a few sprigs and/or forks indicating mild steel, or do you achieve 25″ long, slight to moderate volume of yellow orange sparks, a few forks with intermittent breaks but few if any sprigs to indicate alloy steels or do you get 15″ long short, red sparks in large volume with numerous and repeating sprigs, which are telltale signs of a high carbon metal? Another test, the chisel test, will help indicate the type of metal as well. If the metal fractures in large chunks when you take a chisel to it, this means you have cast iron, which can be very difficult to weld unless using special high-nickel electrodes and heat-treating. On the other hand, if the chisel yields corkscrew-like shavings, you are looking at a weldable steel.

What Is the Goal?

Now that you have identified the base material, you need to assess your final goal. In a farm type setting, you need to ascertain whether you need to strengthen the item or prevent wear? If the item in question is a hitch bar on a tractor, the ultimate goal is strength and ductility so that it will not break. WELD IT! If you are talking about an earth-engaging tool, you don’t want it to wear out. HARDFACE IT!

Identify What Method to Use

There are three types of welding methods to consider. They differ by speed and cost. The methods are all available to all welding and hardfacing products. However, specific products often have properties that are somewhat unique and not exactly duplicated when utilized by a different process.

Stick Welding

Manual or stick welding requires the least amount of equipment and provides maximum flexibility for welding in remote locations and in all positions. Typically, each rod permits welding for about one minute. In seconds, one can change from mild steel to stainless to hardfacing. In seconds, the electrode can change from small to large diameter for small or large welds. Although simplest, this type of welding takes the greatest operator skill.


This type of welding uses wire feeders and continuously fed electrodes. The welding gun is hand-held by the operator. The gun keeps feeding wire as long as the trigger is depressed. This is also much easier to learn than stick welding. This type of setup is becoming more popular on farms, which do more than minimal repair work. Semiautomatic welding increases deposition rates over manual welding because there is no need to stop after burning each rod.


Requiring the greatest amount of initial setup, automatic welding has the highest deposition rates for maximum productivity. The welding gun is carried by a mechanized carriage and the welding operator just pushes a start button. This would rarely be found on a farm, but is common at repair centers for heavy equipment that would rebuild your parts for you if the schedule was mutually acceptable.

Welding Procedures

There are five basic steps when welding that must be followed.Welding and Farming

  • Proper Preparation – You first need to ensure that the metal you are welding is clean and dry. Remove rust, dirt, grease, oil and other contaminants by wire brushing. If not removed, these contaminants can cause porosity, cracking and poor weld deposit quality. You must also remove badly cracked, deformed or work-hardened surfaces by grinding, machining or carbon-arc gouging.
  • Proper Preheat – The combination of alloy content, carbon content, massive size and part rigidity creates a necessity to preheat in many welding or hardfacing operations. Most applications require preheating, as a minimum to bring the part to a room temperature of 70ƒ-100ƒ F. Medium to high carbon and low alloy steels may require higher preheat to prevent underbead cracking, welding cracking or stress failure of the part. Preheating can be done with either a torch, oven or electrical heating device. Special temperature-melting crayons can help you verify proper preheat. Too much heat and you can often ruin alloy materials!
  • Adequate Penetration – Correct Welding Procedure – Identify the correct amperage, travel speed, size of weld, polarity, etc. Make sure the completed weld meets your expectations in regards to size and appearance. Welds should be smooth and uniform, free from undercut or porosity. If possible, watch a video showing the type of welding you will be doing so you know what things are suppose to look like.
  • Proper Cool Down – Preheating is the most effective way of slowing the cooling rate of massive or restrained parts, which are inherently crack sensitive. Insulating the part immediately after welding with dry sand, lime, or a glass fiber blanket also helps minimize residual cooling stresses, weld cracking and distortion. Never quench a weld with ice or water as this will lead to greater internal stresses and potentially weld cracking.
  • Post Weld Heat Treatment – Some items may require tempering or heat-treating. What this means is that you warm the item up with your torch after welding and allow it to slowly cool.


There are a few rules you should follow as you are welding/hardfacing:
Welding and Farming

  • Protect yourself from fumes and gases – Always weld in an open, well-ventilated room and keep your head out of the fumes – especially with hardfacing
  • Wear protective clothing – Protect your eyes and face with a welding helmet designed for arc welding, not just gas welding goggles. In the same manner, protect your body from weld spatter and arc flash with woolen or cotton clothing, a flameproof apron and gloves, and boots. Also make sure to protect others around you from the arc rays as well.
  • Beware of electric shock – Do not touch live electrical parts and make sure that your welding machine is properly grounded. Never weld if you are wet or if your gloves have holes in them.
  • Fire/explosion hazard – Never weld in an enclosed space or near hay, feed bags, gasoline, diesel, hydraulic fluids or anything else that can be within the reach of your welding sparks that would cause a fire or explosion. Never weld alone. Always have a buddy nearby in case of an emergency.


After reading this article, you should be able to reap the benefits of welding in much the same way as you already reap the benefits of the earth on your farm.

Selecting Your Welding Process

Sure, you know you have a weld to make. . .that’s the easy part. . . but you need to start by examining your application.. Everybody’s job is individual and has specific requirements. Therefore, if you’re really confused the best idea is to consult a welding expert in person. If you still have questions after reading this article, just ask us online.

However, this article can help you with welding process selection in four easy steps:

1.) The joint to be welded is analyzed in terms of its requirements.

2.) The joint requirements are matched with the capabilities of available processes. One or more of the processes are selected for further examination.

3.) A checklist of variables is used to determine the ability of the selected processes(s) to meet the particular application.

4.) Finally, the proposed process or processes deemed most efficient are reviewed with an informed representative of the equipment manufacturer for verification of suitability and for more information

Step 1 – Analysis of Joint Requirements.

The first thing to look at is whether your weld joint is large or small, whether the joint is out-of-position or not, and whether the base metal is thick or thin.

In welding, the needs of any joint are expressed in four terms: Fast-Fill (high deposition rate), Fast-Freeze (the joint is out-of-position – overhead or vertical), Fast-Follow (high arc speed and very small welds), and Penetration (the depth the weld penetrates the base metal)

Fast-Fill is required when a large amount of weld metal is needed to fill the joint. A heavy weld bead can only be laid down in minimum arc time with a high deposition rate. However, Fast-Fill becomes a minor consideration when the weld is small.

Fast-Freeze implies that a joint is out-of-position, and therefore requires quick solidification of the molten crater. Not all semiautomatic processes can be used on fast-freeze joints.

Fast-Follow suggests that the molten metal follows the arc at rapid travel speed, giving continuous, well-shaped beads, without “skips” or islands. This trait is especially desirable on relatively small single-pass welds, such as those used in joining sheet metal.

Penetration varies with the joint. With some joints, penetration must be deep to provide adequate mixing of the weld and base metal and with others it must be limited to prevent burnthrough or cracking.

Any joint can be categorized in terms of the previously mentioned four factors. To determine the appropriate welding process, keep your efforts focused on the requirements of the weld joint. A joint that requires, or can be welded by, just one arc welding process is rare. In fact, the majority of joints usually are characterized
by a combination of these requirements to varying degrees. Once you’ve determined your appropriate joint requirements and ranked them, have your assessment reviewed by an experienced engineer or welder. With time and experience, you’ll be able to make these assessments more accurately and with less difficulty.

Step 2 – Matching Joint Requirements With Processes

Your equipment manufacturers’ literature usually will give information on the ability of various processes to fulfill the needs of the joint. (Or, a telephone call or email will bring the needed information.) A wrong answer is virtually impossible at this point, since the deposition rate and arc-speed characteristics of each process can be clearly defined. Since you have characterized your weld joint it is simply a matter of selecting the process that suits your characterization. To view some machines and consumables with various characteristics click here to view Lincoln Electric’s product line.

So what do you do when you find that two or more processes are suitable, which is sometimes the case? You create a checklist!

Step 3 – The Checklist

Considerations other than the joint itself have a bearing on selection decisions. Many of these are specific to your job or welding shop. However, they can be of great importance – and a key factor in eliminating alternate processes. Organize these factors into a checklist and consider them one-by-one:

Volume of Production. You must justify the cost of welding equipment by the amount of work, or productivity, required. Or, if the work volume for one application is not great enough, another application may be found to help offset the costs.

Weld Specifications. Rule out a process if it does not provide the weld properties specified by the code governing the work.

Operator Skill. Operators may develop skill with one process more rapidly than another. Will you have to train your operators in a new process? That adds cost!

Auxiliary Equipment. Every process has a recommended power source and other items of auxiliary equipment. If a process makes use of existing auxiliary equipment, the initial cost in changing to that process can be substantially reduced.

Accessory Equipment. Availability and cost of necessary accessory equipment – chipping hammers, deslagging tools, flux lay-down and pickup equipment, exhaust systems, et cetera – should be taken into account.

Base-Metal Conditions. Rust, oil, fit-up of the joint, weldability of the steel, and other conditions must be considered. These factors could limit the usefulness of a particular process.

Arc Visibility. Is there a problem following irregular seams? Then open-arc processes are advantageous. On the other hand, if there’s no difficulty in correct placement of the weld bead, there are “operator-comfort” benefits with the submerged-arc process; no head-shield required and heat from the arc is reduced.

Fixturing Requirements. A change to a semiautomatic process requires some fixturing if productivity is to be realized. Appraise the equipment to find out if it can adapt to processes.

Production Bottlenecks. If the process reduces unit fabrication cost, but creates a production bottleneck, its value is lost. Highly complicated equipment that requires frequent servicing by skilled technicians may slow up your actual production thereby diminishing its value.

The completed checklist should contain every factor known to affect the economics of the operation. Some may be specific to the weld job or weld shop. Other items might include:

  • Protection Requirements
  • Range of Weld Sizes
  • Application Flexibility
  • Seam Length
  • Setup Time Requirements
  • Initial Equipment Cost
  • Cleanliness Requirements

Evaluate these items realistically recognizing the peculiarities of the application as well as those of the process, and the equipment.

Human prejudice should not enter the selection process; otherwise objectivity is lost – when all other things are equal, the guiding criterion should be overall cost.

Step 4 – Review of the Application by Manufacturer’s Representative.

This may seem redundant, but the talents of experts should be utilized. Thus, the checklist to be used is tailored by the user to his individual situation. You know your application best and your welding expert knows his equipment best. Together, you should be able to confirm or modify the checklist. To contact a Lincoln Electric welding Expert click here.

Systemizing the Systematic Approach.

A system is of no value unless it is used. Create a chart and follow the steps to determining process. By taking the time to analyze each new weld joint, your operation will become more productive and your welding experience will be more fulfilling.

Source: Adapted from The Procedure Handbook of Arc Welding. The Lincoln Electric Company, 1994.

To order a copy of Lincoln Electric’s Procedure Handbook of Arc Welding or other welding textbooks and educational aids, click here to print out and fax an order form.

Arc-Welding Fundamentals
The Lincoln Electric Company, 1994.

Arc welding is one of several fusion processes for joining metals. By applying intense heat, metal at the joint between two parts is melted and caused to intermix – directly, or more commonly, with an intermediate molten filler metal. Upon cooling and solidification, a metallurgical bond is created. Since the joining is an intermixture of metals, the final weldment potentially has the same strength properties as the metal of the parts. This is in sharp contrast to non-fusion processes of joining (i.e. soldering, brazing etc.) in which the mechanical and physical properties of the base materials cannot be duplicated at the joint.

Fig. 1 The basic arc-welding circuit

In arc welding, the intense heat needed to melt metal is produced by an electric arc. The arc is formed between the actual work and an electrode (stick or wire) that is manually or mechanically guided along the joint. The electrode can either be a rod with the purpose of simply carrying the current between the tip and the work. Or, it may be a specially prepared rod or wire that not only conducts the current but also melts and supplies filler metal to the joint. Most welding in the manufacture of steel products uses the second type of electrode.

Basic Welding Circuit

The basic arc-welding circuit is illustrated in Fig. 1. An AC or DC power source, fitted with whatever controls may be needed, is connected by a work cable to the workpiece and by a “hot” cable to an electrode holder of some type, which makes an electrical contact with the welding electrode.

An arc is created across the gap when the energized circuit and the electrode tip touches the workpiece and is withdrawn, yet still with in close contact.

The arc produces a temperature of about 6500ºF at the tip. This heat melts both the base metal and the electrode, producing a pool of molten metal sometimes called a “crater.” The crater solidifies behind the electrode as it is moved along the joint. The result is a fusion bond.

Arc Shielding

However, joining metals requires more than moving an electrode along a joint. Metals at high temperatures tend to react chemically with elements in the air – oxygen and nitrogen. When metal in the molten pool comes into contact with air, oxides and nitrides form which destroy the strength and toughness of the weld joint. Therefore, many arc-welding processes provide some means of covering the arc and the molten pool with a protective shield of gas, vapor, or slag. This is called arc shielding. This shielding prevents or minimizes contact of the molten metal with air. Shielding also may improve the weld. An example is a granular flux, which actually adds deoxidizers to the weld.

Fig. 2 This shows how the coating on a coated (stick) electrode provides a gaseous shield around the arc and a slag covering on the hot weld deposit.

Figure 2 illustrates the shielding of the welding arc and molten pool with a Stick electrode. The extruded covering on the filler metal rod, provides a shielding gas at the point of contact while the slag protects the fresh weld from the air.

The arc itself is a very complex phenomenon. In-depth understanding of the physics of the arc is of little value to the welder, but some knowledge of its general characteristics can be useful.

Nature of the Arc

An arc is an electric current flowing between two electrodes through an ionized column of gas. A negatively charged cathode and a positively charged anode create the intense heat of the welding arc. Negative and positive ions are bounced off of each other in the plasma column at an accelerated rate.

In welding, the arc not only provides the heat needed to melt the electrode and the base metal, but under certain conditions must also supply the means to transport the molten metal from the tip of the electrode to the work. Several mechanisms for metal transfer exist. Two (of many) examples include:

  1. Surface Tension Transfer – a drop of molten metal touches the molten metal pool and is drawn into it by surface tension.
  2. Spray Arc – the drop is ejected from the molten metal at the electrode tip by an electric pinch propelling it to the molten pool. (great for overhead welding!)

If an electrode is consumable, the tip melts under the heat of the arc and molten droplets are detached and transported to the work through the arc column. Any arc welding system in which the electrode is melted off to become part of the weld is described as metal-arc. In carbon or tungsten (TIG) welding there are no molten droplets to be forced across the gap and onto the work. Filler metal is melted into the joint from a separate rod or wire.

More of the heat developed by the arc is transferred to the weld pool with consumable electrodes. This produces higher thermal efficiencies and narrower heat-affected zones.

Since there must be an ionized path to conduct electricity across a gap, the mere switching on of the welding current with an electrically cold electrode posed over it will not start the arc. The arc must be ignited. This is caused by either supplying an initial voltage high enough to cause a discharge or by touching the electrode to the work and then withdrawing it as the contact area becomes heated.

Arc welding may be done with direct current (DC) with the electrode either positive or negative or alternating current (AC). The choice of current and polarity depends on the process, the type of electrode, the arc atmosphere, and the metal being welded.


August 23, 2011

Types and Selection of Drives:

  • Single Unsnubbed Bare / Lagged pulley Drive
  • Snubbed Bare / Lagged Pulley Drive
  • Tandem Drive
  • Special Drives

Single Unsnubbed Bare / Lagged Pulley Drive:

This is the simplest drive arrangement consisting of a steel pulley connected to a motor and the belt wrapped round it on an arc of 180°. This can be used for low capacity short center conveyors handling non-abrasive material. The pulley may be lagged to increase the coefficient of friction.

01-unsnubbed bare pulley-lagging-snub pulley-belt conveyor drive arrangement-driving pulley-tandem drive

Snubbed Bare / Lagged Pulley Drive:

Here the angle of wrap is increased from 180° to 210° or even up to 230°, by providing a snub pulley to the driving pulley. In majority of medium to large capacity belt conveyors, handling mild abrasive to fairly abrasive materials, 210° snub pulley drive with load pulley lagged with hard rubber is adopted.

01-snubbed bare pulley drive-snubbed lagged drive pulley-large capacity belt conveyors-snub pulley-driving pulley

Tandem drive:

Here belt tension estimated to be high; the angle of wrap is increased by adopting tandem drives. Both of tandem pulleys are driven. The tandem drive with arc of contact from 300° to 480° or more can operate with one or two motors. The location of such drive is usually determined by the physical requirements of the plant and structural constraints.

01-tandem drive-two pulley drives-belt conveyor angle of wrap-types of belt conveyor drives-belt conveyor drive arrangement

Special Drive:

Special drives with snub pulleys and pressure belts used in heavy and long conveyors.

01-pressure belts-special belt conveyor drives-tandem drive-driving pulley-special drive with pressure belt


August 22, 2011

01-interview-interview questions-placement paper-interview questions and answers-mechanical interview tips-interview skills-interview preparation

  • Different between technology & engineering?

Engineering is application of science. Technology shows various methods of Engineering. A bridge can be made by using beams to bear the load,by an arc or by hanging in a cable; all shows different technology but comes under civil engineering and science applied is laws of force/load distribution.

  • how a diesel engine works in generator?

Diesel engine is a prime mover,for a generator,pump,and for vehicles etc.generator is connected to engine by shaft.mostly in thermal power plat ,there is an engine is used to drive generator to generate power.


Micrometer’s other name is Screw Gauze & Vernier caliper’s other name is slide caliper.

  • What is flashpoint?

Flash point: the lowest temperature at which the vapor of a combustible liquid can be ignited in air.

  • what is basic difference between impulse turbine and reaction turbine?

In impulse turbine, jet is used to create impulse on blades
which rotates the turbine and in reaction turbine, no jet
is used pressure energy is converted into kinetic energy.

In impulse turbine fluid enter& leave with same energy ,but in reaction turbine fluid enter with pressure energy&
leaves with kinetic energy

In impulse turbine all the pressure drops in nozzle only &
in reaction turbine pressure drops both fixed & moving
blades.the difference is due to blade profiles.

  • What is the need for drafting?

Drafting is the allowance give to casting also used to remove the casting from mould without damage of

  • what is the difference between BSP thread and BSW thread?

The British Standard Pipe thread (BSP thread) is a family
of standard screw thread types that has been adopted
internationally for interconnecting and sealing pipe ends
by mating an external (male) with an internal (female) thread.
British Standard Whitworth (BSW) is one of a number of
imperial unit based screw thread standards which use the
same bolt heads and nut hexagonal sizes.

  • What is refrigerant?

Any substance that transfers heat from one place to another,
creating a cooling effect. water is the refrigerant in absorption machines.

  • The amount of carbon present in Cast Iron

Carbon is basically present in the form of cementite in cast iron.Its percentage lies in the range of 2.03-6.67(% by weight of cementite for Cast Iron.If the amount is less than the above range than it is stainless steel.

  • What are the loads considered when designing the Nut and Bolts?

Shear Loads & crushing loads

  • what is the effect of reheat on rankine cycle? 1.efficiency increases output increases 3. both 4. none of these.

1.Efficiency increases.

this prevents the vapor from condensing during its expansion which can seriously damage the turbine blades, and improves the efficiency of the cycle, as more of the heat flow into the cycle occurs at higher temperature.