Self toughening silion nitride ceramic guide and guard roller and its preparing method

Abstract

The present invention belongs to the field of ceramic material preparing technology, and features that the guide and guard roller is made of material comprising alpha-phase silicon nitride powder 55-85 wt%, ytterbium oxide 10-30 wt% and prefabricated beta-phase silicon nitride crystal seed 5-15 wt%. The making process of the guide and guard roller includes the following steps: mixing alpha-phase silicon nitride powder, beta-phase silicon nitride crystal seed and ytterbium oxide in the weight proportion, ball milling, drying, pelletizing, forming and sintering to obtain guide and guard roller blank, and final finish grinding. The guide and guard roller product has high toughness, high strength, high hardness, high wear resistance, service life as long as 7-8 times that of guide and guard roller of heat resistant steel and greatly raised work efficiency of high speed wire rolling machine.

Description

technical field [0001] The invention relates to a self-toughening silicon nitride ceramic guide roller for high-speed wire rolling and a preparation method thereof, belonging to the technical field of ceramic material preparation. Background technique [0002] The guide device is an important part of the section steel main rolling mill. Its main function is to guide the rolled piece to bite in and out smoothly along the correct route, to straighten the bent rolled piece, and to clamp and straighten the rolled piece. The guide roller is the most critical part in the guide device, which plays a decisive role in realizing the function of the guide device. [0003] During the wire rolling process, the steel billet passes through the guide device at a relatively high temperature (900-1250°C) and at a high speed (above 50m / s). Cooling water with a certain pressure is sprayed on the surface. Therefore, at a relatively high temperature, the guide device not only has to withstand r...

AI Technical Summary

Problems solved by technology

All of the above factors lead to huge material consumption of guide rollers and frequent replacement of guide devices, which has become one of the bottlenecks restricting the normal production of wire rods.

[0004] At present, most of the guide rollers are made of heat-resistant steel and other metal materials. Due to the low hardness and wear resistance of metals at high temperatures, and poor chemical stability at high temperatures, high-temperature wear failures and steel-bonding failures will occur during the use of guide rollers. , strain failure, thermal fatigue and thermal crack failure and other failure forms

In addition, due to the high density of the metal, the heavy guide roller will generate a lot of stress on the bearing installed inside it during high-speed rotating motion, which may easily cause the failure of the bearing