许多重要产品的零件,如传动轴、轧辊、连杆、法兰等,常采用中碳钢制造。中碳钢与低碳钢相比较,中碳钢的含碳量较高,因此在手工电弧焊时,母材近缝区容易产生低塑性的淬硬组织。含碳量越高,这种淬硬倾向就愈大。因此当工件刚度较大和焊条选用不当时,容易产生冷裂纹。同时由于母材熔 Many important product parts, such as drive shafts, rollers, connecting rods, flanges, etc., are often made of medium carbon steel. Medium carbon steel compared with low carbon steel, carbon steel carbon content is higher, so in manual arc welding, the base metal near the seam prone to low plastic hardened tissue. The higher the carbon content, the harder the tendency is. Therefore, when the workpiece stiffness and electrode improper selection, prone to cold cracking. At the same time due to the base metal melting