工业纯铁锻造过程中“红脆”现象的相图分析

Phase Chart Analysis of "Red Brittleness" Phenomenon in the Industrial Pure Iron Forging

通过相图分析可知,奥氏体中的硫的固溶度随着温度急剧降低。如果不采取有效的消除措施,在工业纯铁的锻造过程中,由于过量硫元素的存在,在一个特定温度范围内,纯铁处于固-液两相区。因此,会造成奥氏体晶界位置存在液态薄膜而降低晶粒之间的结合能力,出现所谓的"红脆"现象。有关分析,可以作为实践教学过程中有关相图的应用和重要性的一个生动事例。

As can be seen from the phase chart analysis, the solid solution degree in austenite falls sharply with the descending temperature. If no effective diminishing measures are taken, pure iron would exist in the bi-phase region of liquid and solid in a certain range of temperatures, due to the presence of excessive sulfur. Such status will lead to the reduction of binding capacity because of the existence of liquid film in the grain boundaries in austenite, and thus the so-called ＂ red brittleness＂ phenomenon would occur. The analysis below can be used as a vivid case to demonstrate the application of phase charts and to show its significance in the practice teaching process.