新闻中心


NEWS CENTER

碳钢锻件的过热现象有哪些 Carbon steel forgings overheating phenomenon which

2021-09-15


  碳钢锻件锻造加工前毛坯需要经过加工,那么在加热过程中过热现象是指碳钢锻件所使用的金属坯料的加热温度过高,在规定的锻造与热处理温度范围内停留时间太长,或由于热效应使温升过高而引起的晶粒粗大现象。
 
  碳钢锻件过热之后会出现魏氏组织。马氏体钢过热之后,往往出现晶内织构,工模具钢往往以一次碳化物角状化为特征判定过热组织。钛合金过热后,出现明显的β相晶界和平直细长的魏氏组织。合金钢过热后的断口会出现石状断口或条状断口。过热组织,由于晶粒粗大,将引起力学性能降低,尤其是冲击韧度。
 
  一般锻件厂对过热的碳钢锻件经过正常热处理(正火、淬火)之后,组织可以改善,性能也随之恢复,这种过热常被称之为不稳定过热;而合金结构钢锻件的严重过热经一般的正火(包括高温正火)、退火或淬火处理后,过热组织不能完全消除,这种过热常被称之为稳定过热。
 
  Carbon steel forgings forging before processing blanks need to be processed, then the process of heating in the process of overheating refers to the carbon steel forging the use of metal blanks heating temperature is too high, in the specified forging and heat treatment temperature range of residence time is too long, or due to Thermal effect caused by the temperature rise is too high caused by the phenomenon of coarse grain.
 
  Carbon steel forgings after the overheating will appear Wei's organization. Martensitic steel after the overheating, often appear within the fabric texture, die and die steel is often a carbide angle characteristics to determine the superheat organization. Titanium alloy overheating, there is a clear β-phase grain boundary and straight and elongated Wei's organization. Alloy steel overheating after the fracture will appear stone fracture or strip fracture. Overheated tissue, due to coarse grain, will cause mechanical properties to reduce, especially the impact toughness.
 
  The general forging plant on the overheated carbon steel forgings after normal heat treatment (normalizing, quenching), the organization can improve the performance also will be restored, this overheating is often referred to as unstable overheating; and alloy structural steel forgings serious overheating After the normal normalizing (including high temperature normalizing), annealing or quenching, the superheat tissue can not be completely eliminated, this overheating is often referred to as stable overheating.