Looking to expand your welding skills? Whether you’re a beginner or an experienced welder, this comprehensive guide has got you covered.
From low carbon steel to copper and copper alloys, aluminum and aluminum alloys, titanium and titanium alloys, and even high-strength ordinary low-alloy steel, this article provides in-depth information on how to weld each material type, including recommended welding methods, welding materials, and pre-welding preparation.
So, if you want to improve your welding techniques and produce high-quality welding joints, keep reading!
How to weld low carbon steel?
Low-carbon steel contains a low amount of carbon and exhibits excellent plasticity, making it highly versatile for manufacturing various types of joints and components.
During the welding process, it is unlikely to develop a hardened structure, and the risk of producing cracks and pores is minimal, making it an ideal welding material.
Low-carbon steel can be effectively welded using gas welding, manual arc welding, submerged arc automatic welding, gas-shielded welding, and other techniques to produce high-quality welding joints.
However, when using gas welding, it is essential to avoid overheating, which can cause the grains in the heat-affected zone to enlarge.
If the joint stiffness is high, and the surrounding temperature is low, preheating the workpiece to 100~150℃ is necessary to prevent cracking.
How to weld medium carbon steel?
Medium-carbon steel contains a high carbon content, making it prone to developing a hardened structure and cracks in the weld and its heat-affected zone. Therefore, it is necessary to preheat the steel to approximately 300℃ before welding and allow for slow cooling after welding.
Medium-carbon steel can be welded using gas welding, manual arc welding, and gas-shielded welding methods.
To prevent cracking, it is recommended to use welding rods with excellent crack resistance, such as junction 506 and junction 507.
How to weld aluminum and aluminum alloy?
When welding aluminum and aluminum alloys, it is important to note that they are particularly susceptible to producing oxide films with large and high melting points. These oxide films have the ability to absorb a significant amount of water, making defects such as slag inclusion, poor fusion, and pores common in the welding process. In addition, aluminum alloys are prone to thermal cracking.
While gas welding or manual arc welding can be used to weld aluminum and aluminum alloy, gas welding is generally not preferred due to its low production efficiency and tendency to cause workpiece deformation. This method is only recommended for thin plates.
Currently, AC argon arc welding is widely used to weld aluminum and aluminum alloy due to its concentrated heat, ability to produce beautiful welds with minimal deformation, argon protection, and prevention of slag inclusion and pores.
Manual arc welding is suitable for plates with a thickness greater than 4mm, and the recommended welding rods are aluminum 109, aluminum 209, and aluminum 309. It is important to note that these welding rods are all salt-based electrodes with poor arc stabilization performance, making it necessary to use a DC reverse power supply.
How to weld titanium and titanium alloys?
Titanium is an extremely reactive element that readily interacts with gases such as oxygen, nitrogen, and hydrogen, especially in its liquid and solid states above 600°C. These reactions result in the formation of harmful impurities that weaken the metal.
As a result, oxygen-acetylene gas welding, manual arc welding, or other gas shielded welding methods cannot be used for titanium and its alloys. Instead, welding techniques like argon arc welding, vacuum electron beam welding, and contact welding are recommended.
Argon arc welding is employed to weld thin plates below 3mm in thickness. The power supply is directly connected, and the purity of argon used should not be less than 99.98%.
During welding, the nozzle should be kept as close as possible to the workpiece. Additionally, the welding current should be set at a low level while maintaining a high welding speed.
It is recommended to carry out low-temperature annealing treatment after welding. This process will enhance the crystalline structure and eliminate welding stress, thereby improving the overall quality of the weld.
How to weld copper and copper alloys?
Welding copper and copper alloys poses several challenges due to their excellent thermal conductivity, which can lead to defects such as poor penetration and fusion. Welding may result in significant deformation, cracks, and a high number of pores in the weld and fusion area. Moreover, the mechanical properties of the joint, particularly its plasticity and toughness, are inferior to those of the base metal.
Gas welding can be utilized for red copper, but its efficiency is low, and it requires preheating to over 400 ℃, which may result in considerable deformation. Manual arc welding, on the other hand, can employ copper 107 or copper 227 electrodes. The power supply must be connected in reverse with DC, and the arc should be kept as low as possible. Furthermore, the straight-line round-trip strip transportation method can be used to enhance the weld formation.
To improve the quality of your weld, it’s recommended to hammer it after welding. Tungsten argon arc welding is a good method to achieve high-quality welded joints while minimizing the deformation of the weldments.
When using welding wire, it’s best to use wire 201. However, if you’re using purple copper wire T2, you’ll also need flux 301. The power supply should be connected with DC positive connection.
To avoid pores and slag inclusion, it’s important to thoroughly clean both the workpiece and welding wire before welding. During welding, it’s best to use a large current and high speed.
If you’re welding brass, gas welding is a common method. For this, you can use wire 221, wire 222 or wire 224 as welding wire. These wires contain elements like silicon, tin, iron, and others that can help reduce the burning loss of zinc in the molten pool.
Gas welding has a low temperature, which also helps to reduce the burning loss of zinc in brass. Using a slight oxidation flame to cover the surface of the molten pool with a layer of zinc oxide film can help reduce the evaporation of zinc. Brass can also be welded using manual arc welding or argon tungsten arc welding.
What are the characteristics of ordinary low alloy steel welding?
Low alloy steel is commonly used in manufacturing. When welding this type of steel, the main characteristic is that the heat affected zone of the joint tends to harden significantly, and the presence of hydrogen can lead to cold cracking of the joint.
As the strength grade of ordinary low alloy steel increases, the tendency towards hardening and cold cracking also increases.
What is the welding method of 16 manganese steel?
For welding 16 manganese steel, it is recommended to select alkaline electrodes such as junction 506 or junction 507 and use DC reverse connection.
In cases where the structural crack tendency is low, acidic electrodes such as junction 502 or junction 503 can also be used. The welding process is similar to that of low carbon steel.
In instances where the weldment is rigid and the ambient temperature is below -10℃, preheating is necessary before welding.
Satisfactory results can be achieved by utilizing manual arc welding, submerged arc welding, or electroslag welding.
What is the welding method of No. 15 manganese vanadium and No. 15 manganese titanium steel?
Both 15 manganese vanadium and 15 manganese titanium belong to the category of 40 kg ordinary low alloy steel. The addition of vanadium or titanium enhances the strength grade of the steel. However, their weldability, welding materials, and welding process are not significantly different from welded 16 manganese steel.
When utilizing automatic submerged arc welding, the welding wire can be utilized to weld 08 manganese high and 08 manganese 2 silicon, and by working together with flux 431, flux 350, or flux 250, satisfactory results can be obtained.
How about the welding method of No. 18 Mn Mo Nb steel?
No.18 steel, also known as manganese molybdenum niobium steel, is a type of high-strength ordinary low-alloy steel that weighs 50kg. It is often utilized in the production of critical welding products, including high-pressure vessels and boiler drums.
Due to its robustness and hardening tendency, local heating measures must be taken during spot welding. It is important to dry the welding rod and clean the groove to prevent cold cracks caused by hydrogen.
For manual arc welding, it is recommended to use welding rods like 607. For automatic submerged arc welding, 08 manganese 2 molybdenum high welding wire is preferred, which can be welded with flux 250 or flux 350.