4130 structural steel is widely used in the production of fasteners and high-pressure flanges for steam turbines and boilers. Its weldability is analyzed

highlighting its susceptibility to cold cracking. Measures such as pre-weld heating and post-weld heat treatment are proposed. Taking TIG welding as an example

the overlay welding process is tested using S Ni 6625 filler wire. Non-destructive tests (visual inspection

dye penetrant inspection

bend testing) and destructive tests (macroscopic metallography

microscopic metallography

chemical element analysis

ferrite content

and hardness testing) are conducted to verify the rationality of the TIG overlay welding process. The results show that the selected welding parameters effectively control the generation of cold cracks and yield a high-quality overlay weld. Based on the test results

an overlay welding procedure specification for 4130 structural steel is developed

providing guidance for actual production and manufacturing.