How to Distinguish Forging Crack, Heat Treatment Crack and Raw Material Crack? How to Distinguish Forging Crack, Heat Treatment Crack and Raw Material Crack? – Type of crack: Raw Material Crack, heat treatment crack, forging crack, etc.. Forging cracks can be subdivided into: (1) Forging crack caused by raw material defect; (2) Forging cracks caused by improper forging process. Purpose of forging: (1) Forming requirements; (2) Improve the internal structure of the material, refine the grain, uniform element composition and structure; (3) Make the material more compact, streamline distribution is more reasonable; (4) Through a reasonable post-forging heat treatment, for the next process services. Therefore, forging forging raw material internal defects is the responsibility. Large-scale castings and forgings often start from ingot forging directly. There must be a lot of casting defects in ingot, obviously, reasonable forging, can be one of the so-called”Defects” forging. Therefore, the rationality of forging process […]
crack
Common Crack Types of Pressure Vessels and Pipelines and their NDT Techniques Common crack types of pressure vessels and pipelines: Stress corrosion cracking Stress corrosion crack is a common type of crack, which is related to the interaction of internal and external stress and corrosion medium. Common in the boiler steam pipe and container seat, mainly tied in the pipeline outside. When the pressure on the outer surface of the pipeline exceeds the stress limit of the region, it will inevitably lead to the external deformation and cracking of the pressure pipeline. Mechanical Fatigue Crack Mechanical fatigue cracks are common in rotating machinery parts such as impeller, blade and shaft in boiler auxiliary system. This kind of crack mainly includes two stages, namely, the early stage of long crack propagation and the late stage of tangential crack formation. Therefore, the formation of mechanical fatigue crack is related to the running […]
How to Explain the Cause of the Welding Defects on the Negative Plate 1. Common welding defects can be classified into four categories: 1) Weld size does not meet the requirements: such as ultra-high, ultra-wide, too narrow, too large difference between height and height, weld transition to the base metal is not smooth. 2) Welding surface defects: such as undercut, Weld, concave, overflowing, no penetration, surface porosity, surface cracks, etc. . 3) Weld internal defects: such as porosity, slag inclusion, cracks, non-fusion, tungsten inclusion, double-sided welding, such as the lack of penetration。 4) The properties of welded joint do not meet the requirements: the mechanical properties and corrosion resistance of welded joint are reduced because of over-heating and over-burning. 2. The damage of welding defects to welded components mainly includes the following a spects: 1) Cause stress concentration The distribution of stress in welded joint is very complex. Where there […]