Drip-feed type gas boriding process

Abstract

This invention involves a drip gas boronizing approach. The method contains the steps of: adopting ordinary drip gas carburizing furnace, heating the furnace to the temperature for boronizing, and dropping boriding agent containing trimethyl borate, methanol and chloridated rare earth and methanol to the furnace, decomposing and to form boride on the steel surface through adsorption and diffusion of boron atom decomposed by trimethyl borate. The invention has the advantage of uniform and compact leaking layer, good surface quality, Layer depth and surface boron content can be controlled; no need of cleaning workpiece after infiltration, with directly quenching after infiltration and low labor intensity; penetration enhancers without rank poison, non-explosive, with relatively good and safe, reliable working environment, without specialized equipments, commonly used carburizing furnace can meet the requirements, can handle all sorts of shapes and sizes workpiece, can be easy to achieve automatic control, with high efficiency, easy operation and high applicability.

Description

technical field

[0001] The invention relates to a metal heat treatment method, more specifically to a drop-injection gas boronizing method. Background technique

[0002] Boron is located before the carbon element in the second period of the periodic table, and its atomic radius is larger than that of carbon and nitrogen, and its ratio to the atomic radius of transition metals is greater than 0.59. Therefore, the compounds formed by boron and transition metals have a much larger The interstitial phase has a much more complex crystal structure. The metal compounds such as FeB, Fe2B, TiB2, ZrB2, VB2, CrB2 have high hardness and good thermal stability, which are higher in hardness and thermal stability than corresponding carbides and nitrides, but it is difficult to cut and other deformation processing. Generally, for steel used in machinery manufacturing, a large amount of boron cannot be added during the smelting process, and only a small amount of boron can be added to impr...