Professional testing platform: brief description of metal material failure analysis process

Date：2021-09-18 17:55:29Views：932

The failure analysis of metal materials focuses on the phenomenon that the mechanical or mechanical parts and components can not better complete the specified function or the mechanical components lose the original design function due to the change of size, shape, material performance or structure during the use of structural parts (or in the test process before use). So as to find out the main causes of structural member failure, as well as failure prevention measures and product improvement scheme tips.

There are two situations in the failure part of the product: failure caused by internal defects; Failure caused by surface defects.

In terms of classification, there are elastic failure, plastic failure, corrosion failure, brittle fracture failure, fatigue failure, ductile fracture failure and wear failure.

Most of the reasons for failure are improper material selection or defects, unreasonable design, unqualified process and improper operation and maintenance.

The common defects of metal material failure are segregation and shrinkage. Loose, bubbles and white spots. This kind of defect belongs to cast steel metal defect.

The defects of forged and rolled steel generally include: coarse widmanstatten structure, folding, scratch, network carbide and banded structure, decarburized layer structure, crack, delamination and scar. In addition, welding process and metal inclusions have a great influence on the properties of metal materials.

In failure analysis, the deformation and fracture of materials are often problems. Deformation failure at room temperature or low temperature, the deformation failure is mainly composed of elastic deformation failure and plastic deformation failure. Elastic deformation failure is mainly excessive deformation or loss of the elastic function of the original design, and plastic failure is generally excessive deformation. The deformation failure at high temperature includes creep failure and thermal relaxation failure. It generally includes elastic deformation failure, plastic deformation failure, high temperature deformation failure and fracture deformation failure, including ductile fracture, brittle fracture and fatigue fracture. The wear failure and failure analysis report mainly includes abrasive wear, adhesive wear, impact wear, fretting wear, corrosion wear and fatigue wear.

Generally speaking, we can analyze the specific causes of material failure through structural analysis, nondestructive testing analysis, stress test calculation, material performance test and chemical composition analysis.