Butt welding elbow is a kind of using steel by hot pressing molding technology or forging forming technology of production of the elbow, the connection method is through the elbow with the steel pipe butt welding, using resistance heat two artifacts along the entire face welded together at the same time, the two methods usually have butt welding and flash butt welding, high productivity, easy automation, so has won a wide range of applications.
Butt welding elbow electrode should be kept dry, when using titanium calcium type should be 1 hour after 150 ℃ drying, low hydrogen type should be 1 hour after the 200-250 ℃ drying (can’t repeat drying, otherwise the skin easy cracking flake), prevent electrode surface sticky oil and other dirt, lest cause weld increased carbon content and affects the quality of weldment. When the welding elbow, carbide precipitation by repeated heating, reduce corrosion resistance and mechanical properties.
Butt welding elbow during the welding process needs to be in accordance with the instructions and the form of actual control, make its elbow products can fully show the use of good characteristics and performance, ensure the quality of the good contribution and.
The butt welding elbow generally have a 45 degree Angle, 90 degree Angle, 180 – degree Angle and so on, the material is carbon steel, alloy steel and stainless steel. According to its radius of curvature to points, can be divided into long radius elbow and short radius elbow. Long radius of bend radius of curvature is equal to 1. 5 times the pipe diameter, that is, R = 1. 5 d. Bend radius of curvature is equal to the pipe diameter, short radius R = 1 d. Type D bend diameter of R for the radius of curvature. If no specific instructions, general selection is 1.5 D bend.
Sclerosing after welding is bigger, easy to crack. If using the same type of electrode welding, must be above 300 ℃ preheat and 700 ℃ or so slow cooling after welding. If cannot undertake the weldment heat treatment after welding, it should choose chromium nickel stainless steel electrode. To improve the gb elbow corrosion resistance and weldability and appropriately increased moderate stability element Ti, Nb and Mo, weldability is better, using the same type of chromium stainless steel electrode, should be above 200 ℃ preheat and around 800 ℃ tempering treatment after welding.
If cannot undertake the weldment heat treatment, should choose chromium nickel stainless steel electrode. In gb elbow welding need to follow certain standards and forms, need according to the use of good form and process for making and welding, can fully show the value of a good contribution.
Source: Yaang Pipe Industry Co., Limited (www.yaang.com)