Production method for hard carbide with graded distributed cobalt content

Abstract

The hard alloy producing process includes compounding material, wet milling, adding glue, molding to form, loading the plain blank into boat, covering with pure carbon black, sintering in sintering furnace under the protection of hydrogen, and post-treatment to eliminate internal stress and to obtain the hard alloy with gradiently distributed Co content. Owing to the sintering and carburizing with pure carbon black as carburizing agent and the increased post-treatment step, the advanced technological process has high reliability, strong carburizing reaction activity, simple operation process, obvious Co content gradient in the hard alloy product, high comprehensive mechanical performance, low production cost, and other advantages.

Description

technical field [0001] The invention belongs to a production method of hard alloy products, in particular to a production method of hard alloy products in which the content of cobalt element in the hard alloy body changes gradually from the surface to the inside. The method is especially suitable for the production and manufacture of tools and molds such as WC-Co cemented carbide blades (tools) and stretching molds, so as to improve their comprehensive mechanical properties. Background technique [0002] Conventional WC-Co hard alloy blades, drill teeth, rock cutting and wire drawing dies have uniform internal and external metallographic structures and consistent mechanical properties. This kind of cemented carbide products with uniform structure has a contradiction between high hardness and wear resistance and toughness that is difficult to reconcile, that is, when the content of cobalt (Co) in the alloy is reduced to improve its hardness and wear resistance, the alloy body...

AI Technical Summary

Problems solved by technology

However, there are: first, two-step sintering, long production cycle and high production cost; second, the use of Al 2 o 3 Filling with fine powder not only prevents the alloy body from fully contacting with the carburizing atmosphere, but also causes decarburization reaction with the sintered body; carburizing through gas carbon source requires high equipment control accuracy and operation process control, and the carburizing reaction activity is low. The carburizing time is long and the formation speed of the structural gradient is slow; the third is the quality and shape accuracy, poor stability, easy deformation and other side effects caused by the change of the organizational structure after carburizing and sintering-the formation of cobalt antimony degree, so that it can only produce Products with a certain height and width ratio for geological drilling, such as button teeth and column teeth, cannot meet the production requirements of products such as alloy blades and wire drawing dies that require high quality and precision.

Therefore, this background technology has high requirements for equipment control precision and operation process control, long production cycle, high production cost, low carburizing reaction activity, long carburizing time, slow Co gradient formation speed, and the quality and shape precision of the produced products Poor stability, not suitable for the production of blades, wire drawing dies and other products with high quality and precision requirements

Images