SPA-H steel performance qualification rate 100%

Based on the principle of controlled rolling and controlled cooling, this paper studies the effect of rolling process parameters on SPA-H, formulates a reasonable rolling process for weathering steel SPA-H, and successfully develops a new steel grade SPA-H. The main research results are as follows:

(1) Based on the principle of controlled rolling, the effect of temperature regime on the microstructure and properties of SPA-H steel was studied. The heating temperature range of SPA-H is determined to be 1200-1250℃; the final rolling temperature of rough rolling is 1040-1080℃; the finishing rolling temperature is controlled to 840-880℃; the coiling temperature is 640-580℃, compared Reasonable.

(2) When heating and out of the furnace: 1200℃, the furnace time: more than 160 minutes; 3+3 passes are used for rough rolling, the thickness after rolling is 40mm, and the temperature after rolling (RT2 temperature): 1060℃; finishing rolling Temperature: 850℃; Coiling temperature: 630℃; Laminar flow method: sparse cooling; SPA-H steel developed through this rolling process meets the national standards for various mechanical properties.

(3) The yield strength of SPA-H steel with a coiling temperature of 600℃ is 425~435MPa, the tensile strength is 525~535MPa, and the elongation is 39~43.5%. It shows that reducing the coiling temperature, refining the grains and improving the comprehensive properties of SPA-H steel.

(4) When the coiling temperature is set to 560℃ and the finish rolling temperature is 880℃, the ferrite band structure is eliminated, and the microstructure can be improved by increasing the cooling rate.

(5) Optimize the rolling process system of SPA-H steel: the heating temperature is 1220℃, the rough rolling temperature is 1180℃, and the finishing rolling temperature is 1050℃; the finishing rolling temperature is 1020℃, and the finishing rolling temperature is 1020℃. 880℃, coiling temperature 560℃. After trial rolling in small batches, the performance qualification rate of SPA-H steel is 100%, which can meet the needs of customers.