40CrNi2MoV钢应力松弛特性研究

为获得４０ＣｒＮｉ２ＭｏＶ钢的高温松弛性能，对该材料进行了松弛试验研究。试验数据经回归和高通量得到了所有用于表征材料抗松弛性能的材料常数，并得到与试验结果吻合良好，可反映松弛全过程的松弛曲线表达式。试验结果表明，该材料具有良好的抗松弛性能。还对工程应用中的不同初应力，松弛应变速率和试验结果外推等问题进行了讨论，认为当材料的松弛极限较高时，在强度允许的条件下，有可能通过加大初应力来延长服役周期或减小

Experimental Research on the Properties of Stress Relaxation for 40CrNi2MoV Bolt Steel

Stress relaxation tests are performed for 40CrNi2MoV bolt steel to obtain the properties of stress relaxation.Using the expression proposed by authors,all material constants which characterize the relaxation behavior of the metal at high temperatures are obtained.The Relaxation curve fitted with the proposed expression coincides with experimental data within the scope of whole relaxation process.The result of study shows that 40CrNi2MoV has good property to resist relaxation.Some issues are discussed,such as prediction of remaining stress under conditions of varied initial stress values,variation of relaxation strain rate during relaxation procedure and extrapolation of experimental results.It is thought that initial stress may be increased to lengthen period of service or to reduce dimensions of parts,if relaxation limit stress is higher.