孕育处理是指在凝固过程中，向液态金属中添加少量其它物质，促进形核、抑制生长，达到细化晶粒的目的。习惯上，向铸铁中加入添加剂称为孕育处理；向有色合金中加入添加剂则称变质处理。 从本质上说，孕育处理主要影响形核和促进晶粒游离；而变质处理则是改变晶体的生长机理（抑制长大），从而影响晶体形貌。

        
        作用

灰铸铁的力学性能在很大程度上取决于其显微组织。未经孕育处理的灰铸铁，显微组织不稳定、力学性能低下、铸件的薄壁处易出现白口。为保证铸件品质的一致性，孕育处理是必不可少的 [1]。

铸铁孕育处理所用的孕育剂，加入量很少，对铸铁的化学成分影响甚小，对其显微组织的影响却很大，因而能改善灰铸铁的力学性能，对其物理性能也有明显的影响。良好的孕育处理有以下作用：

◆消除或减轻白口倾向；

◆避免出现过冷组织；

◆减轻铸铁件的壁厚敏感性，使铸件薄、厚截面处显微组织的差别小，硬度差别也小；

◆有利于共晶团生核，使共晶团数增多；

◆使铸铁中石墨的形态主要是细小而且均匀分布的A型石墨，从而改善铸铁的力学性能。

孕育良好的铸铁流动性较好，铸件的收缩减少、加工性能改善、残留应力减少。

Inculation treatment refers to the addition of a small amount of other substances to the liquid metal during the solidification process to promote nucleation, inhibit growth, and achieve the purpose of refining grains. Traditionally, adding additives to cast iron is called inoculation; The addition of additives to non-ferrous alloys is called metamorphism. Essentially, inoculation treatment mainly affects nucleation and promotes grain dissociation; Metamorphic treatment is to change the growth mechanism of the crystal (inhibit growth), thereby affecting the morphology of the crystal.

function

The mechanical properties of gray cast iron are largely determined by its microstructure. Gray cast iron without inoculation treatment has unstable microstructure, low mechanical properties, and white mouth is easy to appear on the thin wall of the casting. In order to ensure the consistency of the quality of the casting, inoculation treatment is essential [1].

The inoculant used in the inoculation treatment of cast iron is very small, which has little effect on the chemical composition of cast iron, but has a great impact on its microstructure, so it can improve the mechanical properties of gray cast iron and has a significant impact on its physical properties. Good inoculation treatment has the following effects:

◆ Eliminate or alleviate the tendency of white mouth;

◆ Avoid supercooling tissues;

◆ Reduce the sensitivity of wall thickness of iron castings, so that the difference in microstructure between thin and thick sections of castings is small, and the difference in hardness is also small;

◆It is conducive to the nucleation of eutectic clusters and increases the number of eutectic clusters;

◆ The form of graphite in cast iron is mainly fine and evenly distributed A-type graphite, so as to improve the mechanical properties of cast iron.

陕西科目金属材料有限公司

Shaan Xi Ke Mu Metal Materials ,.CO LTD

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