Research and Development of 625 Alloy Hot Extrusion Forming and Seamless Steel Tube

The 625 alloy hot-extruded blank tube was obtained by using the glass-lubricated hot-extrusion process , and the 625 alloy seamless steel tube with a specification of ( | ) 19x 1.65mm was developed through multi-pass cold rolling. The results show that: the average grain size of the 625 alloy seamless pipe is about 7 grades, and it has good process performance and mechanical properties (the yield strength at room temperature can reach more than 414MPa ). At the same time, the 625 alloy seamless pipe has good corrosion resistance, and the intergranular corrosion rate of the G28A method is lower than 0.9mm/a .

Experimental conditions
of 625 alloy, the extrusion temperature is 1080-12509, the tool heating temperature is 300-350 ° C , and the maximum extrusion force is 35MN . Research on cold working process of 625 alloy seamless pipe, the cold deformation is 20-60% . Corrosion resistance test: ASTM G28A method 600ml 50 %H 2 SO4+25gFe 2 SO4 solution.
Main research content and conclusion
The research on the hot extrusion process of product-grade 625 alloy was carried out on a 35MN steel extrusion machine . The cold working behavior of 625 alloy was studied by cold rolling forming process . The research results show that: when the heating temperature of the billet is between 1100-1200°CW , the 625 alloy has good extrudability, the average grain size of the extruded tube can reach about grade 6 , and the yield strength at room temperature can reach above 414MPa . The 625 alloy has a high work hardening behavior. When the deformation exceeds 50% , the work hardening is very obvious, and the hardness can reach about 410HB (44HRC) . Using the ASTM G28A method, the corrosion resistance of the 625 alloy seamless pipe was evaluated, and the results showed that the corrosion rate was about 0.5mm/a .

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