CN103276313B - High-speed steel roll collar and heat treatment method - Google Patents

Abstract

The invention relates to a high-speed steel roll ring and a heat treatment method. The elements are composed by weight percentage: C: 1.3-1.9, B: 0.4-0.8, Cr: 3.0-5.0, Si: 0.5-0.9, Mn: 0.6-1.3 , V: 2.0-10.0, Ni: 0.5-1.5, Mo: 1.0-4.0, Nb: 0.1-2.0, Co: 4.5-5.0, Al: 0.3-0.4, Ti: 0.02-0.04, Zr: 0.05-0.2, S <0.04, P<0.04, the rest is Fe. The invention greatly improves the wear resistance, heat resistance, and thermal shock resistance of the alloy, reduces the phenomenon of thermal fatigue cracks and the resulting meat loss and cracking of the roll during use, and reflects good safety and wear resistance sex. The invention is applied to a high-speed wire rod rolling mill.

Description

A high-speed steel roll ring and heat treatment method

technical field

The present invention relates to the field of steel rolling machinery, in particular to a high-speed steel roll ring and a heat treatment method.

Background technique

Since my country introduced the first high-speed wire rod mill production line from abroad in 1986, it has developed extremely rapidly. At present, more than 100 high-speed wire rod mill production lines have been built in my country, and the total output of high-speed wire products is close to 50% of the total wire rod output. As the speed of the rolling mill increases, the requirements for the quality of the rolls are getting higher and higher, especially the requirements for the surface hardness of the rolls are getting higher and higher. Commonly used roll materials are high-chromium cast iron and high-nickel-chromium infinitely chilled cast iron, but in the pre-finishing section and finishing section of the high-speed wire rod mill production line, due to the small roll diameter and high rotation speed, roll rings and roll shafts are usually used. The combined rolls are mechanically combined, and the roll ring is made of cemented carbide through powder metallurgy. The cost is high and the brittleness is high. During use, roll bursting and peeling are prone to occur, which affects rolling production. Therefore, solving the material problem of the roll ring is an effective measure to improve the efficiency of steel rolling operations and steel quality, reduce consumption, reduce labor intensity of workers, and reduce accidents. The use environment of the roller ring is harsh, and its performance is demanding. The material of the roller ring must have excellent mechanical properties. At present, only the roller ring in my country has spent more than 3 billion yuan in funds to develop suitable materials and preparation methods for the roller ring and apply it to rolling equipment. On the one hand, it will definitely promote the rapid development of the steel rolling industry and save a lot of resources.

Contents of the invention

The purpose of the present invention is to provide a high-speed steel roller ring and a heat treatment method that can ensure excellent mechanical properties of the roller ring, reduce production costs, and improve the quality of the produced steel.

The present invention is achieved in the following way: a high-speed steel roll ring, characterized in that: the components of each element are: C: 1.3-1.9, B: 0.4-0.8, Cr: 3.0-5.0, Si: 0.5-0.9, Mn:0.6－1.3, V:2.0－10.0, Ni:0.5－1.5, Mo:1.0－4.0, Nb:0.1－2.0, Co:4.5－5.0, Al:0.3－0.4, Ti:0.02－0.04, Zr: 0.05－0.2, S<0.04, P<0.04, the rest is Fe.

The present invention includes the following steps: annealing, quenching and tempering for 2-3 times. During annealing, the roller ring is heated to 800-860°C with the furnace, and after the furnace is cooled to less than 500°C, it is furnace cooled or air-cooled; during quenching, the roller ring is heated to 1020°C with the furnace. -1150°C, then air-cooled or air-cooled; during tempering, the roller ring is heated to 500-550°C with the furnace, then furnace-cooled or air-cooled, tempered 2-3 times under the same process.

The invention greatly improves the wear resistance, heat resistance, and thermal shock resistance of the alloy, reduces the phenomenon of thermal fatigue cracks and the resulting meat loss and cracking of the roll during use, and reflects good safety and wear resistance sex.

Detailed ways

A high-speed steel roll ring, characterized in that: the composition of each element by weight percentage is: C: 1.3-1.9, B: 0.4-0.8, Cr: 3.0-5.0, Si: 0.5-0.9, Mn: 0.6-1.3, V :2.0－10.0, Ni:0.5－1.5, Mo:1.0－4.0, Nb:0.1－2.0, Co:4.5－5.0, Al:0.3－0.4, Ti:0.02－0.04, Zr:0.05－0.2, S＜0.04 , P<0.04, the rest is Fe. The heat treatment method of high-speed steel roller rings includes the following steps: annealing, quenching and 2-3 times of tempering. During annealing, the roller rings are heated to 800-860°C with the furnace, cooled to less than 500°C in the furnace, and then furnace-cooled or air-cooled; The ring is heated to 1020-1150°C with the furnace, then air-cooled or air-cooled; when tempering, the roller ring is heated to 500-550°C with the furnace, then furnace-cooled or air-cooled, and tempered 2-3 times in the same process. During specific implementation, the present invention obtains high-hardness MC-type carbides by increasing the content of carbon and vanadium in the molybdenum-containing high-speed steel. On this basis, more cobalt elements are added to increase the secondary hardening of the high-speed steel. ability, red hardness and high temperature hardness, thereby improving the high temperature wear resistance of the roller ring. An appropriate amount of aluminum is also added to further increase the red hardness of the roll and improve the high temperature wear resistance. The addition of aluminum can also improve the shape of carbides and promote the distribution of carbides from continuous network to broken network and isolated distribution. Adding an appropriate amount of niobium can reduce the segregation of vanadium in the centrifugal casting process of the roller ring, and make the structure and performance of the roller ring uniform. Adding a small amount of rare earth, titanium, zirconium and other elements aims to refine the structure and improve the uniformity of carbide distribution. Improve the comprehensive performance of the roller ring, ensure the safe use of the roller ring, and realize the large-scale production and industrial application of the high-speed steel roller ring. Due to the high content of carbon, vanadium, cobalt, molybdenum and other elements, the hardness after heat treatment is high, the hardness uniformity of the roller surface is good, and the wear resistance is good. The hardness reaches 69-71HRC, and the hardness difference of the roller surface is less than 1.5HRC. Due to the addition of cobalt, molybdenum, aluminum and other elements, the roller ring has excellent red hardness, and the red hardness at 625 °C reaches 59-62HRC, which makes the roller ring have excellent wear resistance at high temperatures. It can not only be used for high-speed wire rods The pre-finishing stand of the rolling mill can also be applied to the finishing stand of the high-speed wire rod mill. Among them, rare earth, titanium, zirconium, aluminum and other elements after smelting have fine structure and uniform distribution of carbides, so they have high bending strength, reaching 1850-1960Mpa, and impact toughness greater than 10J/cm ² . It does not contain high-density tungsten elements, and the addition of niobium can eliminate the segregation of vanadium elements, so the element segregation of the roll ring is light, the structure and performance of the roll ring diameter are uniform, and the hardness drop within 35mm in the radial direction of the roll body is less than 2HRC.

The roll ring produced by the present invention has a good effect on high-speed wire rolling mills.

Example 1

Used on the high-line pre-finishing mill stand, the effect is as follows: rolling ordinary steel: 5500-6000t/single groove, grinding amount 0.5-0.7mm/side; rolling hard wire steel: 3500-4000t/single groove, grinding Amount of 0.6 ~ 0.8mm / single side.

Example 2

It is used on the high-speed finish rolling stand, and the effect is as follows: rolling ordinary steel: 1200～1500t/single groove, grinding amount 0.5～0.7mm/side; rolling hard wire steel: 750～900t/single groove, grinding amount 0.6～0.8mm/one side.

The amount of rolled steel and the amount of grinding of the roll ring of the present invention, no matter it is applied to the high-line pre-finishing stand or the finishing stand, has reached the level of the hard alloy roll ring, but the production cost is lower than that of the hard alloy roll The ring is reduced by 40-50%, and the disadvantages of the hard alloy roll ring being explosive and peeling off are overcome, the production cost of the rolled material is reduced, and significant economic and social benefits are obtained.

Claims (2)

1. a high speed steel roll collar, is characterized in that: each elemental composition is by weight percentage: C:1.3-1.9, B:0.4-0.8, Cr:3.0-5.0, Si:0.5-0.9, Mn:0.6-1.3, V:2.0-10.0, Ni:0.5-1.5, Mo:1.0-4.0, Nb:0.1-2.0, Co: 4.5-5.0, Al:0.3-0.4, Ti:0.02-0.04, Zr:0.05-0.2, S < 0.04, P < 0.04, all the other are Fe.

2. the heat treating method of a kind of high speed steel roll collar according to claim 1, it is characterized in that: comprise the following steps: annealing, quenching and 2-3 tempering, during annealing, collars is heated to 800-860 DEG C with stove, the cold or air cooling of stove after stove is chilled to and is less than 500 DEG C; During quenching, collars is heated to 1020-1150 DEG C with stove, subsequently air-cooled or air cooling; During tempering, collars is heated to 500-550 DEG C with stove, subsequently cold the or air cooling of stove, tempering 2-3 time under same process.