测量表面硬化深度方法

[中文适用范围]： 表面硬化可以定义为一种以这样的方式硬化含铁材料的过程，即表面层（称为外壳）比其余材料（称为芯部）硬得多。该工艺包括渗碳、渗氮、碳氮共渗、氰化、感应和火焰硬化。在每种情况下，化学成分、机械性能或两者都会受到这种做法的影响。该测试程序描述了测量化学成分或机械性能变化深度的各种方法。每种产品都有其经过实践证明的应用领域，并且不提倡使用单一方法来满足所有目的。用于确定表面深度的方法可以是化学的、机械的或视觉的，并且样本或零件可以在软的或硬化的条件下进行所描述的测试。然后，测得的硬化层深度可报告为硬化样本上的有效硬化层深度或总硬化层深度，以及未硬化样本上的总硬化层深度。应当认识到，由不同方法确定的渗层深度之间的关系可能有很大差异。影响这种关系的因素包括外壳特性、母材成分、淬火条件等。例如，在某些情况下，不可能通过化学或目视手段来预测有效渗层深度。因此，重要的是根据具体要求仔细选择渗层深度的确定方法，并符合经济性。 [外文原描述]： Case hardening may be defined as a process for hardening a ferrous material in such a manner that the surface layer, known as the case, is substantially harder than the remaining material, known as the core. The process embraces carburizing, nitriding, carbonitriding, cyaniding, induction, and flame hardening. In every instance, chemical composition, mechanical properties, or both are affected by such practice.This testing procedure describes various methods for measuring the depth to which change has been made in either chemical composition or mechanical properties. Each procedure has its own area of application established through proved practice, and no single method is advocated for all purposes.Methods employed for determining the depth of case are either chemical, mechanical, or visual, and the specimens or parts may be subjected to the described test either in the soft or hardened condition. The measured case depth may then be reported as either effective or total case depth on hardened specimens, and as total case depth on unhardened specimens.It should be recognized that the relationship between case depths as determined by the different methods can vary extensively. Factors affecting this relationship include case characteristics, parent steel composition, quenching conditions, and others. It is not possible to predict, in some instances for example, effective case depth by chemical or visual means. It is important, therefore, that the method of case depth determination be carefully selected on the basis of specific requirements, consistent with economy.Cross Reference: