CN102699104A

CN102699104A - Preparation method of G20CrNiMo bearing steel pipe

Info

Publication number: CN102699104A
Application number: CN201210189621XA
Authority: CN
Inventors: 顾铭; 李伟国; 龚建峰; 金惠明; 密燕芳; 王雪亚
Original assignee: CHANGSHU XUANLI BEARING STEEL TUBES Co Ltd
Current assignee: CHANGSHU XUANLI BEARING STEEL TUBES Co Ltd
Priority date: 2012-06-11
Filing date: 2012-06-11
Publication date: 2012-10-03

Abstract

The invention relates to a preparation method of a G20CrNiMo bearing steel pipe and belongs to the technical field of steel pipe preparation. The preparation method comprises the following steps that G20CrNiMo round steel is subjected to perforation at the temperature being 1150 to 1200 DEG C to obtain a pipe blank, the perforation eccentricity is controlled to be smaller than 8 percent, and the surface defects of the pipe blank are controlled; the pipe blank is sent into a heating furnace to be heated to 860 to 880 DEG C, in addition, the heat insulation is carried out for 40 to 80 minutes, the heat insulation is carried out for 280 to 320 minutes when the temperature of the pipe blank is lowered to 670 to 700 DEG C along with the furnace, the furnace discharge is carried out when the temperature is lowered to 150 DEG C at the temperature lowering speed being 45 to 55 DEG C/hour, and an annealing pipe blank is obtained; the annealing pipe blank is subjected to acid washing, phosphorization and saponification lubrication to obtain a pipe blank to be rolled; the pipe blank to be rolled is introduced into a pipe rolling machine to be rolled, the number of the reciprocating times of a machine head frame of the pipe rolling machine is 55 to 65 times/minutes, the feeding length of the pipe blank in each time is 6 to 8mm, and a rolled pipe is obtained; the rolled pipe is introduced into the heating furnace to be heated to 680 to 710 DEG C, in addition, the heat insulation is carried out for 45 to 60 minutes, the rolled pipe is cooled to the room temperature along with the furnace, and then, the furnace discharge is carried out, and the G20CrNiMo bearing steel pipe is obtained. The strong impact load can be born, the wear resistance is realized, and the service life of the bearing is ensured.

Description

The preparation method of G20CrNiMo bearing steel pipe

Technical field

The invention belongs to the steel pipe preparing technical field, be specifically related to a kind of preparation method of G20CrNiMo bearing steel pipe

Background technology

bearing steel pipe is prepared through a series of operation by bearing steel; The operation that the bearing steel of the different trades mark prepares the bearing steel pipe is different; And the technological parameter in each operation is different; With the trade mark is that 1010 steel are example; Its process is: add hot piercing (heating-up temperature is 1200-1250 ℃), cold rolling (extending multiple 1.8-2.5), intermediate heat-treatment (steel pipe is sent into continuous annealing furnace 700-800 ℃ of annealing with the speed of 0.6-0.7m/min), cold-drawn (the extension multiple is 1.3-1.5) and finished product heat treatment (technological parameter is identical with intermediate heat-treatment), and can be to this referring to CN101386037B.Again, bearing steel can be divided into following three kinds by the difference of its chemical composition and quality percentage: one is high carbon bearing steel, its trade mark or title grade of steel such as GCr4, GCr15, GCr9, GCr9SiMn, GCr15SiMn etc.; Two is carburizing bearing steel, its trade mark such as G20CrMo, G20CrNiMo, G20CrNi2Mo, G20Cr2Ni4 and G10CrNi13Mo etc.; Three is the stainless steel bearing steel, its trade mark such as 9Cr18 and 9Cr18Mo etc.

aforesaid high carbon bearing steel has hardness high-wear resistance excellence and is widely used in making common rolling bearing, more particularly is used to make the lasso (lasso comprises bearing inner race and bearing outer ring) of rolling bearing.Yet high carbon bearing steel not suitable for making is used for the inside and outside circle of bearing of rotation at a high speed, because the bearing of the rotation of the high speed on the heavy mechanical equipment is also comparatively harsh for anti-contact fatigue strength and hot-workability except hardness and wearability are had the requirement.So the roller bearing that adopts the trade mark of standard among the CNS GB/T3203-1982 to process for the G20CrNiMo bearing steel is usually filled the post of the bearing of rotation at a high speed; This is because very good, the wearability of case hardness and contact fatigue strength are excellent after the G20CrNiMo alloy carburizing steel Carburization Treatment, can bear high impact load because of heart portion also keeps good toughness simultaneously.The G20CrNiMo steel is former to be the grade of steel 8620 in U.S. AISI, the SAE standard; Quenching degree is close with the 20CrNi steel, though the content of Ni is the half the of 20CrNi steel in the steel, owing to add a small amount of Mo element is arranged; The top of austenite isothermal transformation curve is moved right; Because of suitably having improved the content of Mn, cause its quenching degree still excellent again, strength ratio 20CrNi steel is high.

Perhaps from technologic secret factor; In disclosed patent and non-patent literature, all be not seen in the method that the G20CrNiMo bearing steel is prepared the bearing steel pipe; The applicant has carried out long-term and good try for this reason, and the technical scheme that will introduce below produces under this background

Summary of the invention

task of the present invention is to provide a kind of preparation method of G20CrNiMo bearing steel pipe; The G20CrNiMo bearing steel pipe that is obtained by this method had both had excellent surface hardness and wearability behind the machining bearing lasso, have the toughness of standing out from one's fellows again concurrently and can bear strong shock loading and use the roller bearing that is applied to heavy mechanical equipment.

Task of the present invention is accomplished like this, and a kind of preparation method of G20CrNiMo bearing steel pipe may further comprise the steps:

A) add hot piercing, the G20CrNiMo round steel 1150-1200 ℃ of down perforation, is obtained pipe, and the control punch eccentricity is less than 8% and control pipe surface blemish;

B) annealing; Pipe is sent into heating furnace be heated to 860-880 ℃ and insulation 40-80min; Then be incubated 280-320min when being cooled to 670-700 ℃ with stove, insulation finishes to come out of the stove when back rate of temperature fall with 45-55 ℃/h is cooled to 150 ℃ then, obtains the pipe of annealing;

C) roll pre-treatment, will anneal pipe pickling, phosphatization and saponification are lubricated, obtain pipe to be rolled;

D) rolling, it is rolling that pipe to be rolled is introduced pipe mill, and the headstock reciprocal time of pipe mill is 55-65 time/min, and each length of sending to of pipe is 6-8 ㎜, obtains rolled pipe;

E) stress relief annealing is introduced heating furnace with rolled pipe and is heated to 680-710 ℃ and insulation 45-60min, comes out of the stove after cooling to normal temperature with the furnace, obtains G20CrNiMo bearing steel pipe.

in a concrete embodiment of the present invention, steps A) described in control pipe surface blemish be meant avoid that there is pit on the pipe surface, runs over and injure, burr, crackle and/or stick up skin.

the resulting G20CrNiMo bearing of technical scheme provided by the invention steel pipe can bear strong shock loading owing to have desirable toughness; After implementing carburizing in the process of making bearing ring by Production of bearing manufacturer; Can make bearing ring show desirable case hardness and use the embodiment wearability, the roller bearing that obtains can be used on the big machinery and can bear strong impact and ensure the service life of bearing.

The specific embodiment

Embodiment 1:

are that 40.7 ㎜ and wall thickness are that the G20CrNiMo bearing steel pipe of 4.9 ㎜ is an example with the preparation aperture.

A) adding hot piercing, be that the G20CrNiMo bearing steel of 55 ㎜ is that round steel (also can claim pole) is 1175 ℃ of perforation down in temperature with diameter, and the control punch eccentricity is less than 8%; Obtaining the aperture is 57 ㎜, and wall thickness is the pipe of 6 ㎜, and pipe is carried out visualize; Use the burr of removing the pipe surface and/or stick up skin; If the pipe surface tangible pit occurs, runs over and injure and/or crackle, then should reject, avoid flowing into subsequent processing;

B) annealing; Will be by steps A) aperture that obtains is that 57 ㎜ and wall thickness are that the pipe of 6 ㎜ is sent into heating furnace and is heated to 880 ℃ and insulation 40min;, furnace temperature is incubated 320min when reducing to 670 ℃ then; Then insulation finishes to come out of the stove when back rate of temperature fall with 50 ℃/h is cooled to 150 ℃, obtains the pipe of annealing;

C) roll pre-treatment; To by step B) to carry out pickling, phosphatization and saponification successively lubricated for the annealing pipe that obtains; Obtain pipe to be rolled, belong to conventional and be the known operation of industry because pickling, phosphatization and saponification are lubricated, so the applicant no longer gives unnecessary details this;

D) rolling; Will be by step C) to introduce pipe mill rolling for the pipe to be rolled that obtains; By roll mill headstock reciprocal time is 60 times/minute, and headstock whenever makes a round trip, and the length of sending to of pipe is 6-8 ㎜; The each length of sending to that is pipe is 6-8mm, obtains the aperture and be 40.7 ㎜ and wall thickness is the rolled pipe of 4.9 ㎜;

E) stress relief annealing; Will be by step D) heating furnace that rolled pipe is introduced that obtains is heated to 680 ℃ and insulation 60min; Cool to room temperature with the furnace or claim and come out of the stove behind the normal temperature, obtain the G20CrNiMo bearing steel pipe of aperture 40.7 ㎜ and wall thickness 4.9 ㎜, annealing hardness: HBW≤229 of pressing CNS GB/T3203 standard; Actual measurement HBW165-185 meets standard-required; Microscopic structure: be not more than 3 grades by GB/T3203 regulation banded structure, survey 1.5 grades, meet standard-required.

Embodiment 2:

are only with steps A) in the hot piercing temperature that adds change 1200 ℃ into; With step B) in the temperature of sending into heating furnace heating change 860 ℃ into, temperature retention time changes 80min into, is incubated 280min when being cooled to 700 ℃ with stove then, insulation finishes to come out of the stove when the back is cooled to 150 ℃ with the rate of temperature fall of 55 ℃/h then; With step D) in the reciprocal time of the roll mill headstock change 55 times/min into; With step e) in heating-up temperature change 710 ℃ into, temperature retention time changes 45min into, all the other are all with the description to embodiment 1.

Embodiment 3:

Only with steps A) in the hot piercing temperature that adds change 1150 ℃ into; With step B) in the temperature of sending into heating furnace heating change 870 ℃ into, temperature retention time changes 60min into, is incubated 300min when being cooled to 685 ℃ with stove then, insulation finishes to come out of the stove when the back is cooled to 150 ℃ with the rate of temperature fall of 52 ℃/h then; With step D) in the reciprocal time of the roll mill headstock change 65 times/min into; With step e) in heating-up temperature change 695 ℃ into, temperature retention time changes 50min into, all the other are all with the description to embodiment 1

Claims

1. A kind of preparation method of G20CrNiMo bearing steel pipe is characterized in that may further comprise the steps:

2. The preparation method of G20CrNiMo bearing steel pipe according to claim 1 is characterized in that steps A) described in control pipe surface blemish be meant avoid that there is pit on the pipe surface, runs over and injure, burr, crackle and/or stick up skin