In the fields of mechanical manufacturing, mold processing, and engineering machinery, high-carbon steel (with a carbon content of 0.6%-1.7%) is often used to make key components such as cutting tools, gears, and shafts due to its high strength and hardness. However, welding high-carbon steel has always been an industry challenge, as it is extremely prone to cracking after welding, which not only affects the service life of the workpiece but may also cause safety accidents. This article will analyze the core reasons for cracking in high-carbon steel welding, recommend suitable welding equipment, and provide equipment selection suggestions to help practitioners break through the technical bottlenecks in high-carbon steel welding.
I. Choosing the Right Equipment Is Key, and Three Types of Welding Machines Are Suitable for High-Carbon Steel Welding
Aiming at the pain points of high-carbon steel welding, ordinary welding machines (such as ordinary manual arc welding machines) cannot precisely control heat input and lack stress relief functions, making it difficult to avoid cracking. It is necessary to choose specialized equipment with the capabilities of "low heat input welding," "stress control," and "dehydrogenation." The following three types of welding machines are more suitable:
Pulsed TIG Welding Machine: Suitable for Precision Welding of Thin-Walled High-Carbon Steel
The pulsed TIG welding machine achieves "precise control of heat input" through periodic pulse current output. The peak current of the pulse is used to melt the metal to form a molten pool, while the base current maintains the stability of the arc and reduces heat input, effectively reducing the size of the heat-affected zone and the probability of martensite formation. Its advantage lies in the beautiful weld seam formation and no spatter. It is suitable for thin-walled high-carbon steel parts with a thickness of less than 3 mm (such as precision mold inserts and small cutting tools). Moreover, argon gas protection can reduce hydrogen ingress and lower the risk of hydrogen-induced cracking.
However, the welding efficiency of pulsed TIG welding machines is relatively low. They require manual wire feeding and have high technical requirements for operators, making them unsuitable for large-batch thick plate welding.
Low-Hydrogen Manual Arc Welding Machine (with Preheating Function): Suitable for Conventional Welding of Medium-Thickness Plates
The low-hydrogen manual arc welding machine, used in conjunction with low-hydrogen electrodes, can effectively isolate the air with the electrode coating, reducing the incorporation of hydrogen and thereby lowering the risk of hydrogen-induced cracking at the source. Some high-end models are equipped with a preheating function that can preheat the workpiece to 150-300°C, slowing down the cooling rate, suppressing the formation of martensite, and releasing some thermal stress. This type of welding machine has a low operational threshold and is suitable for medium-thickness high-carbon steel parts with a thickness of 5-20 mm (such as gears and shaft parts). Moreover, the equipment cost is moderate, offering good value for money.
Gas Metal Arc Welding Machine (MIG/MAG, with Dual-Pulse Function): Suitable for Large-Batch Thick Plate Welding
The MIG/MAG welding machine with dual-pulse function controls droplet transfer through high-frequency pulses, achieving "low heat input and high deposition efficiency." It can both reduce the width of the heat-affected zone to avoid excessive quenched structures and increase welding speed to meet the needs of large-batch production. During welding, an argon-rich mixed gas is used, which offers better protection than pure argon and can further reduce hydrogen ingress. Some models also have a "stress relief" mode that helps release welding stress by adjusting the current waveform.
This type of welding machine is suitable for thick high-carbon steel parts with a thickness of more than 8 mm (such as engineering machinery load-bearing structures and large gear box housings). However, the equipment cost is relatively high, and it needs to be used in conjunction with specialized low-hydrogen welding wire.
II. Equipment Selection Should Be Based on the Scenario, and Processes Should Be Combined to Further Prevent Cracking
When selecting welding equipment for high-carbon steel, it is necessary to make a comprehensive judgment based on the thickness of the workpiece, production batch size, and precision requirements:
For small-batch precision thin-walled parts, the pulsed TIG welding machine is the first choice. It should be used with argon gas protection and post-weld low-temperature tempering to further eliminate stress.
For medium and small batch medium-thickness parts, the low-hydrogen manual arc welding machine offers better value for money. It needs to be combined with processes such as electrode drying, workpiece preheating (for thick plates), and post-weld slow cooling (covering with asbestos cloth).
For large-batch thick plate parts, the dual-pulse MIG/MAG welding machine is more suitable. It can be used with automatic wire feeding and post-weld dehydrogenation treatment to improve efficiency and quality.
If you have welding machine requirements, please contact Ms. Zhao
Founded in 2006, PDKJ is a professional supplier of welding automation solutions. The company has passed the ISO9001 international quality management system certification, has more than 70 officially authorized and applied national patents, and a number of core technologies in the welding field fill the technical gap at home and abroad. It is a national high-tech enterprise.
