Quantcast BACKHAND WELDING

Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Custom Search
 
  
Figure 15-32.—Forehand welding. Figure 15-33.—Backhand welding. welding rod back and forth in opposite semicircular paths, you balance the heat to melt the end of the rod and the side walls of the joint into a uniformly distributed molten puddle. As the flame passes the rod, it melts off a short length of the rod and adds it to the puddle. The motion of the torch distributes the molten metal evenly to both edges of the joint and to the molten puddle. This method is used in welding most of the lighter tubing and sheet metals up to 1/8 inch thick because it permits better control of a small puddle and results in a smoother weld. The forehand technique is not the best method for welding heavy metals. BACKHAND WELDING.—In this method the torch tip precedes the rod in the direction of welding, and the flame is pointed back at the molten puddle and the completed weld. The end of the rod is placed between the torch tip and the molten puddle. The welding tip should make an angle of about 45° to 60° with the plates or joint being welded (fig. 15-33). Less motion is required in than in the forehand method. the backhand method If you use a straight Figure 15-34.—Four basic welding positions. welding rod, it should be rotated so that the end will roll from side to side and melt off evenly. You may also bend the rod and, when welding, move the rod and torch back and forth at a rapid rate. If you are making a large weld, you should move the rod so as to make complete circles in the molten puddle. The torch is moved back and forth across the weld while it is advanced slowly and uniformly in the direction of the weld. You’ll find the backhand method best for welding material more than 1/8 inch thick. You can use a narrower “V” at the joint than is possible in forehand welding. An included angle of 60° is a sufficient angle of bevel to get a good joint. It doesn’t take as much welding rod or puddling for the backhand method as it does for the forehand method. By using the backhand technique on heavier material, it is possible to obtain increased welding speeds, better control of the larger puddle, and more complete fusion at the root of the weld. Further, by using a reducing flame with the backhand technique, a smaller amount of base metal is melted while welding a joint. Backhand welding is seldom used on sheet metal because the increased heat generated in this method is likely to cause overheating and burning. When welding steel with a backhand technique and a reducing flame, the absorption of carbon by a thin surface layer of metal reduces the melting point of the steel. This speeds up the welding operation. WELDING POSITIONS.—The four basic welding positions are shown in figure 15-34. Also shown are four 15-25



Aviation News
Airbus and Oracle Team USA: one step closer to the 2017 America’s Cup yacht race
Airbus’ technology partnership with the Oracle Team USA sailing squad...
airbus.com
Airbus A350 XWB – Welcome and “Grüß Gott” in Munich
First visit of an A350 XWB to Munich International Airport...
airbus.com
Airbus increases A320 rate, adjusts A330 for NEO transition
Airbus has decided to further increase the production rate for...
airbus.com
CPI Scores $49 Contract to Provide US Air Force T-38C Modification Kits
[Avionics Today 02-27-2015] CPI Aerostructures has won a $49 million...
aviationtoday.com
Lockheed Martin Upgrades Royal Australian Air Force C-130J Maintenance Training
Lockheed Martin C-130J virtual maintenance trainer. Photo: Lockheed Martin [Avionics...
aviationtoday.com
CPI Scores $49 Million Contract to Provide US Air Force T-38C Modification Kits
[Avionics Today 02-27-2015] CPI Aerostructures has won a $49 million...
aviationtoday.com
Airbus A350 XWB makes its “première” in Paris
Xtra mature, reliable, innovative, efficient, comfortable Share this Read more...
airbus.com
Raytheon to Support US Air Force Aicraft Integration, Life Cycle
[Avionics Today 02-26-2015] The U.S. Air Force has awarded a...
aviationtoday.com
Raytheon to Support US Air Force Aircraft Integration, Life Cycle
[Avionics Today 02-26-2015] The U.S. Air Force has awarded a...
aviationtoday.com
ViaSat Upgrades Airborne ISR for Canadian Department of National Defense
[Avionics Today 02-26-2015] The Canadian Department of National Defense is...
aviationtoday.com
Saab Selects AEL Sistemas as Avionics Systems Supplier on Gripen NG Fighter
Saab Gripen NG. Photo: Saab AB [Avionics Today 02-25-2015] Saab...
aviationtoday.com
Orbital ATK Completes Installs for South Korean Aircraft Survivability Equipment
[Avionics Today 02-25-2015] Orbital ATK has completed the installation and...
aviationtoday.com
Borealis Alliance: Upping ATM Efficiency through Free Route Airspace
Branka Subotic, executive director of the Borealis Alliance. Photo: Borealis...
aviationtoday.com
Blakey Departs AIA
[Avionics Today 02-24-2015] Marion Blakey will be leaving her post...
aviationtoday.com
Jonal Laboratories Inks Contract with Pratt & Whitney as Production Ramps Up
Jonal Laboratories has signed a long-term agreement with Pratt &...
aviationtoday.com
Rockwell Collins’ New Office Extends Reach in the Middle East
Rockwell Collins has recently expanded its presence in the Middle...
aviationtoday.com
Rockwell Collins Completes Sydney Facility Expansion for DAS Production
Rockwell Collins F-35 DAS. Photo: Rockwell Collins [Avionics Today 02-20-2015]...
aviationtoday.com
Airbus Helicopters Confirms Commitment to Middle East Armed Forces
 Airbus Helicopters recently reinforced their presence in the Middle East...
aviationtoday.com
Engility Wins Contract to Test and Integrate New Avionics into Navy Systems
[Avionics Today 02-20-2015] Engility Holdings won a $27.6 million contract...
aviationtoday.com
Airbus selects the 100 teams for Round Two of the Fly Your Ideas global student challenge
Strong showing from Asia Pacific, Europe and the Americas Share...
airbus.com


Privacy Statement - Copyright Information. - Contact Us

comments powered by Disqus

Integrated Publishing, Inc.
9438 US Hwy 19N #311 Port Richey, FL 34668

Phone For Parts Inquiries: (727) 755-3260
Google +