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The hardness of bearing steel, the hardness of the bearing steel


24th September 2013 Bearing Technology 0 Comments

The bearing steel has high hardness, tensile strength, is exposed to the fatigue strength and wearability, equivalent toughness, respond to the request that and is able to bear high temperature behavior to corrosion resistance under certain condition.

High-carbon bearing steel high in carbon chromium ‘ 0.95-1.05% ,Can obtain high and homogeneous hardness after quenching, fatigue is longe-lived, the shortcoming is able to bear great loaded impact ductility badly slightly. The high-carbon chromium bearing steel is mainly used as one set of cycle sums rolling element of antifriction bearing under general service conditions. Cementation bearing steel low in carbon ‘ Not greater than 0.23% ,After carburizing, the surface hardness is improved, and the core still has good toughness, can bear greater shock load. Used mainly for producing and receiving the bearing with bigger shock load in large-scale machinery. High-carbon chromium become rusty the bearing steel high in carbon ‘ 0.90-1.05% ,Therefore have sufficient corrosion resistance while obtaining high hardness, are used mainly for producing the bearing working under the abominable corrosion condition. The hardness of the high-temperature bearing steel is high, and can still keep quite high hardness at the operating temperature up to 430oC, the high-temperature strength is good, have certain oxidative stability, processing characteristics is better, are used mainly for producing high-temperature engine bearing.

The bearing is used The hardness after steel GCr15 collar of the bearing and roller are quenched: HRC 61-65

Reference standard Antifriction bearing Common technology regular GB307.3

The bearing is used The hardness after steel GCr15 collar of the bearing and roller are quenched: HRC 61-65

Reference standard Antifriction bearing Common technology regular GB307.3

The bearing is used The hardness after steel GCr15 collar of the bearing and roller are quenched: HRC 61-65

Reference standard Antifriction bearing Common technology regular GB307.3

It is a vertical distance of 550HV1 from surface of the part to Vickers hardness number.

Applicable scope:

—This detecting means is suitable for cementation and carbonitriding to harden layer; After heat treatment, on quench, harden the intersection of layer and deep, the hardness number is less than the part of 450HV from the intersection of surface and 3. As to from the intersection of surface and on quench, harden the intersection of layer and deep the intersection of place and hardness number, higher than steel one of 450HV 3, originally determine the way is applicable too, the precondition is to choose the hardness number to be greater than 550HV regard 25HV as first grade A certain lasting demarcation line hardness.

Represent the method:

—Layer is indicated by CHD deeply in quench hardening, the unit is mm. Such as CHD =0.5mm.

—Determine it is 9.807N 1kgf that Vickers hardness number adopts experimental strength . The special circumstances can choose 4.903N-9.807N, namely the threshold value of hardness can use the other values beyond 550HV1.

Determine deeply:

1,The making of the sample: Generally take a sample on the finally hot and treated work piece vertically, and carry on essential grinding and is polished the making that please consult the metallography sample . Determine on the diameter of the prototype workpiece. The special circumstances can adopt the furnace sample.

2,Measuring method: In the width W It is in 1.5mm range the width of namely the test zone ,Determine the Vickers hardness at one string or the intersection of multiterm and parallel line that transverse to surface of the part ‘ Generally adopt two . Distance S of the adjacent impression centre of every two It is 2.5 times more diagonal to be should not be smaller than the impression, is paid and come as a hard blow at piecemeal and tests according to the straight line way. One by one adjacent impression from centre to the intersection of part and distance difference of surface ‘ Namely a2- a1 ,Should not exceed 0.1mm. The range accuracy of measuring the impression centre to the surface of the part should be within the range of ± 0.25um, and diagonal survey accuracy of pressure mark of each hardness should be within ± 0.5um. Experimental strength generally adopts HV0.1 –HV1 obtains the Vickers hardness impression, and adopt above 400X magnification.

3,Confirm deeply: According to two or the multiterm tested The impression routes, confirm hardness number of routing of each impression as 550HV to the distance on the surface of the part, if the difference of two stripline number values is less than or equal to 0.1mm, fetch their mean value as the depth of floor of quench hardening. If difference is greater than 0.1mm, should test again.










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