The effect of hot stamping parameters on the mechanical properties of 22MnB5 steel sheet with thickness of 1.1mm is studied.The considered parameters are austenization temperature(800-1 000 ℃),austenitizing soaking time(60-540s),initial deformation temperature(560-800 ℃)and tool temperature(20-220 ℃).In order to obtain hot stamped parts with optimal mechanical properties,response surface methodology based on the central composite design has been employed to design the experiment matrix.Tensile strength of hot stamped parts is determined as the relation in the mathematical model.The optimal condition and objective effects of parameters are determined via this relation.The statistical analysis showed that all four factors significantly affect the tensile strength of the hot stamped parts.The optimum austenization temperature is found to be 918.89 ℃ with the austenitizing soaking time,initial deformation temperature and tool temperature of 279.45 s,684.69 ℃ and 21.85 ℃,respectively.These optimal hot stamping parameters prove to have high tensile strength(1 631.84MPa)where deviation between predicted and actual response falls within 2%.
0.05).HIF-1αand Sema4D protein expression was significantly correlated with prognosis of colorectal carcinoma,as determined by Spearman rank correlation analysis(r=0.567;P
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)
'/%3e%3cuse xlink:href='%23a' transform='rotate(144 450 300)'/%3e%3cuse xlink:href='%23a' transform='rotate(216 450 300)'/%3e%3cuse xlink:href='%23a' transform='rotate(288 450 300)'/%3e%3c/svg%3e)