How to weld low carbon steel, medium carbon steel, aluminum alloy, titanium alloy, copper alloy and ordinary low alloy steel?
How to weld low carbon steel?
Table of Contents
- How to weld low carbon steel?
- How to weld medium carbon steel?
- How to weld aluminum and aluminum alloy?
- How to weld titanium and titanium alloy?
- How to weld copper and copper alloy?
- What are the welding characteristics of common low alloy steel?
- How about the welding method of 16 Mn steel?
- What are the welding methods of 15 Mn V and 15 Mn Ti steel?
- What is the welding method of No.18 Mn Mo Nb steel?
Low carbon steel has low carbon content and good plasticity. It can be made into various types of joints and components.
In the welding process, it is not easy to produce hardened structure, the tendency to produce cracks is very small, and it is not easy to produce pores. It is the best welding material. Gas welding, manual arc welding, automatic submerged arc welding and gas shielded welding can obtain good welding joints.
When gas welding is used, do not heat for a long time, otherwise the grain size of heat affected zone is easy to grow. When the joint stiffness is large and the ambient temperature is low, the workpiece should be preheated to 100 ~ 150 ℃ to avoid cracks.
How to weld medium carbon steel?
Due to the high carbon content of medium carbon steel, the weld and its heat affected zone are easy to produce hardened structure and cause cracks. Therefore, it is necessary to preheat to about 300 ℃ before welding and slow cooling after welding.
It can be welded by gas welding, manual arc welding and gas shielded welding. Welding materials should be made of welding electrodes with better crack resistance, such as 506 and 507.
How to weld aluminum and aluminum alloy?
Aluminum and aluminum alloy in welding is particularly easy to produce a large scale, high melting point oxide film, this oxide film can also absorb a lot of water, so it is easy to produce slag inclusion, poor fusion and porosity and other defects in welding, in addition, aluminum alloy is easy to produce hot cracks.
Gas welding or manual arc welding can be used for welding aluminum and aluminum alloy. But gas welding heat is not concentrated, aluminum heat transfer is very fast, so the production efficiency is low, the workpiece deformation is large, except for thin plate, it is rarely used.
At present, a large number of aluminum and aluminum alloys are welded by AC argon arc welding, because of its concentrated heat, beautiful weld, small deformation, argon protection, can prevent slag inclusion and porosity.
If manual arc welding is used to weld aluminum, it is suitable for thick plate with thickness of more than 4mm. The welding rod grades are al 109, Al 209 and Al 309. They all belong to the base type electrode and have poor arc stability, so DC reverse connection power supply is required.
Titanium is a very active element. In liquid state and solid state above 600 ℃, it is easy to react with oxygen, nitrogen, hydrogen and other gases to form harmful impurities, which makes titanium brittle.
Therefore, oxygen acetylene gas welding, manual arc welding or other gas shielded welding can not be used for titanium and titanium alloy, but argon arc welding, vacuum electron beam welding and contact welding can only be used. Argon arc welding is used to weld the thin plate less than 3mm. The power supply is directly connected. The purity of argon gas is not less than 99.98%. The nozzle should be close to the workpiece as far as possible. The welding current should be small and the welding speed should be fast. Generally, low temperature annealing should be carried out after welding to improve the crystal structure and eliminate the welding stress.
There are many difficulties in the welding of copper and copper alloy, because of their excellent thermal conductivity, it is easy to cause defects such as incomplete welding and poor fusion. After welding, the workpiece will produce large deformation, and the weld and fusion zone are easy to produce cracks and a large number of pores. The mechanical properties of the joint, especially the plasticity and toughness, are lower than those of the base metal.
Gas welding can be used to weld red copper, but the efficiency is too low, deformation is large, and preheating to 400 ℃ above, the working conditions are not good. For manual arc welding, copper 107 or copper 227 welding rod can be used. The power supply is connected in reverse direction. The arc is kept as low as possible. The linear round-trip rod transportation method is used to improve the weld formation.
Hammer the weld after welding to improve the weld quality. If TIG welding is used, high quality welding joint can be obtained and welding deformation can be reduced. Welding wire 201, if using copper wire T2, but also with flux 301. The power supply adopts DC positive connection. The workpiece and welding wire should be cleaned carefully to reduce the porosity and slag inclusion. High current and high speed should be used in welding.
The welding wire can be wire 221, wire 222 or wire 224. These welding wires contain silicon, tin, iron and other elements, which can reduce the burning loss of zinc in the bath.
Because of the low temperature of gas welding, the burning loss of zinc in brass can be reduced, and the evaporation of zinc can be reduced by covering the surface of molten pool with a layer of zinc oxide film by using slight oxidation flame. In addition, brass can also be welded by manual arc welding and tungsten argon arc welding.
The common low alloy steel is commonly used in reproduction. The main characteristic of this kind of steel welding is that the heat affected zone of the joint has a greater tendency to harden, and the hydrogen content will lead to the cold crack of the joint.
With the increase of the strength grade of ordinary low alloy steel, the tendency of hardening and cold cracking increases.
How about the welding method of 16 Mn steel?
The welding of 16 manganese steel should be made of basic electrode such as Jie 506 or Jie 507, and DC reverse connection. When the tendency of structural crack is small, acid electrode such as Jie 502 or Jie 503 can be used. The welding process is similar to that of low carbon steel;
When the rigidity of the weldment is large and the ambient temperature is lower than – 10 ℃, it is necessary to heat before welding. Satisfactory results can be obtained by manual arc welding, submerged arc welding or electroslag welding.
What are the welding methods of 15 Mn V and 15 Mn Ti steel?
Both 15 Mn V and 15 Mn Ti belong to 40 kg grade ordinary low alloy steel. The strength grade of steel is improved by adding some vanadium or titanium;
But their weldability, welding materials and welding process are not much different from that of welding 16 manganese steel. When automatic submerged arc welding is used, welding wire can be used to weld 08 Mn high and 08 Mn 2 Si, and satisfactory results can be obtained with flux 431, flux 350 or flux 250.
What is the welding method of No.18 Mn Mo Nb steel?
No.18 manganese molybdenum niobium steel belongs to 50 kg grade high strength ordinary low alloy steel, which is commonly used to manufacture important welding products such as high pressure vessel and boiler drum.
Because of its high strength and hardening tendency, local heating should be adopted in spot welding. Pay attention to dry the welding rod and clean the groove to prevent the cold crack caused by hydrogen. Welding rod such as jie607 is used for manual arc welding; 08 manganese 2 molybdenum high welding wire is used for submerged arc welding, which can be welded with flux 250 or flux 350.
Source: China China Flanges Manufacturer – Yaang Pipe Industry (www.epowermetals.com)
(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)
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