Gray cast iron welding process

Abstract

The invention discloses a gray cast iron welding process. The gray cast iron welding process is characterized by including: (1), thermally treating before welding: charging a gray cast iron weldment into a furnace at low temperature, heating the gray cast iron weldment to specified temperature of 600-800 DEG C at a speed about 100 DEG C / h, holding temperature in the furnace for 2-4 h, and cooling the weldment to below 300 DEG C at a cooling speed of 20-50 DEG C / h; (2), drying a welding rod: adopting a Z308 nickel-based cast iron welding rod, drying the same at 150-400 DEG C, and holding the temperature for 1-2 h; (3), welding: adopting a CO2 gas protection welding method, wherein welding current is 50-100 A, electric arc voltage is 15-20 V, gas flow is 8-10 L / min, a welding material is H08Mn2SiA with diameter of 0.8-1 mm. The gray cast iron welding process has the advantages of strict and reasonable control on parameters at each stage and standard procedures, weldability of gray cast iron is improved, and cracks are reduced.

Description

technical field [0001] The invention belongs to the field of welding technology, in particular to a gray cast iron welding technology. Background technique [0002] The output of gray cast iron accounts for the largest proportion in all kinds of castings. The annual output of gray cast iron in my country is about 7 million tons. What is unsatisfactory is that castings with various casting defects account for about 10-15% of the annual output. )%, which is a huge number. If defective castings cannot be repaired by welding, 800,000 to 1,200,000 tons of castings will be scrapped every year. In addition, finished cast iron parts will also be damaged during use, and defects such as cracks will appear. If a reasonable welding process is not adopted To be repaired, the loss of its economic interests is very large. The cracks that are most likely to occur during welding of cast iron are divided into cold cracks and hot cracks. Contents of the invention [0003] In view of the de...

AI Technical Summary

Problems solved by technology

If defective castings cannot be repaired by welding, 800,000 to 1,200,000 tons of castings will be scrapped every year. In addition, finished cast iron parts will also be damaged during use, and defects such as cracks will appear. If a reasonable welding process is not adopted If it is repaired, the loss of its economic interests will be great