CN105986090A - Heat treatment process for bearing steel - Google Patents

Abstract

The invention discloses a heat treatment process for bearing steel. The heat treatment process is characterized by comprising the following steps: 1) normalizing: as for a chromium bearing steel normalizing process, after a workpiece is thoroughly heated, the workpiece is maintained at the temperature for 40 to 60 min, cooling is rapidly carried out, and spheroidizing annealing is immediately carried out after normalizing; 2) spheroidizing annealing: the workpiece is heated to 900 to 920 DEG C before annealing, the temperature of the workpiece is maintained for 2/3 to 1 h before normalizing, and heat preservation time depends on the size of the workpiece, uniformity of a heating furnace, a charging method, a charging amount and uniformity of an original structure before annealing; 3) quenching: quenching temperature of Cr15 steel is in a range of 820 to 860 DEG C, a critical oil quenching diameter is 25 mm, an oil quenching manner is used, the heating and heat preservation time of Cr15 steel is longer than the heating and heat preservation time of alloy tool steel, the heating coefficient of a salt bath is 0.8 to 1.5 min/mm, and the heating coefficient of an air furnace is 1.5 to 2 min/mm; and 4) tempering: tempering is carried out at a low temperature of 460 +/- 10 DEG C for 2 to 4 h. The process provided by the invention is simple, omits a great number of repeated procedures and has improved work efficiency.

Description

A kind of Technology for Heating Processing of bearing steel

Technical field

The present invention relates to the Technology for Heating Processing of a kind of bearing steel.

Background technology

The specification that quenching technical that at present bearing steel uses is more complicated, the most unified, not unified standard, the steel part quality causing production is uneven, a lot of operations that repeat also make under production efficiency, increase the work burden of workman, make the competitiveness of product in market the highest simultaneously.For the operator that some have just been entered a profession, the method technique that neither one is clear and definite, often there are mistakes and omissions when of causing operation, in some instances it may even be possible to cause serious consequence.

Summary of the invention

Because the drawbacks described above of prior art, the technical problem to be solved is to provide the Technology for Heating Processing of a kind of bearing steel, and this process is simple, eliminates a lot of repeatability operation, improves work efficiency.

For achieving the above object, the invention provides the Technology for Heating Processing of a kind of bearing steel, comprise the steps, 1) normalizing: chromium bearing steel normalizing process, insulation 40 ~ 60min after workpiece is diathermanous, cooling needs very fast, transfers spheroidizing after normalizing immediately to；

2) spheroidizing: need to be heated to 900 ~ 920 DEG C before annealing, normalizing after insulation 2/3 ~ 1h, depending on temperature retention time is with the original structure uniformity before workpiece size, the uniformity of heating furnace, shove charge method and batch, annealing；

3) quenching: Cr15 steel hardening heat is at 820 ~ 860 DEG C, and oil quenching cut off diameter is 25mm, typically uses oil quenchinng, and the heating and thermal insulation time is longer than alloy tool steel, salt bath heating coefficient value 0.8 ~ 1.5min/mm, air furnace heating coefficient 1.5 ~ 2min/mm；

4) tempering: using the lonneal of 460 DEG C ± 10 DEG C, tempering time is generally 2 ~ 4h.

The invention has the beneficial effects as follows: present invention process is simple, eliminate a lot of repeatability operation, improve work efficiency.

Detailed description of the invention

Technical scheme disclosed by the invention is the Technology for Heating Processing of a kind of bearing steel, comprises the steps, 1) and normalizing: chromium bearing steel normalizing process, insulation 40 ~ 60min after workpiece is diathermanous, cooling needs very fast, transfers spheroidizing after normalizing immediately to；

2) spheroidizing: need to be heated to 900 ~ 920 DEG C before annealing, normalizing after insulation 2/3 ~ 1h, depending on temperature retention time is with the original structure uniformity before workpiece size, the uniformity of heating furnace, shove charge method and batch, annealing；

3) quenching: Cr15 steel hardening heat is at 820 ~ 860 DEG C, and oil quenching cut off diameter is 25mm, typically uses oil quenchinng, and the heating and thermal insulation time is longer than alloy tool steel, salt bath heating coefficient value 0.8 ~ 1.5min/mm, air furnace heating coefficient 1.5 ~ 2min/mm；

4) tempering: using the lonneal of 460 DEG C ± 10 DEG C, tempering time is generally 2 ~ 4h.

This invention improves working (machining) efficiency, yield rate, reduce production cost, achieve the unforeseeable technique effect of those skilled in the art, overcome design set for a long time, provide a kind of new design and processing thought, and achieve more more preferable processing effect than prior art.

The preferred embodiment of the present invention described in detail above.Should be appreciated that those of ordinary skill in the art just can make many modifications and variations according to the design of the present invention without creative work.Therefore, all technical staff in the art, all should be in the protection domain being defined in the patent claims the most on the basis of existing technology by the available technical scheme of logical analysis, reasoning, or a limited experiment.

Claims (1)

1. the Technology for Heating Processing of a bearing steel, it is characterised in that comprise the steps, 1) normalizing: chromium bearing steel normalizing process, insulation 40 ~ 60min after workpiece is diathermanous, cooling needs very fast, transfers spheroidizing after normalizing immediately to；

2) spheroidizing: need to be heated to 900 ~ 920 DEG C before annealing, normalizing after insulation 2/3 ~ 1h, depending on temperature retention time is with the original structure uniformity before workpiece size, the uniformity of heating furnace, shove charge method and batch, annealing；

3) quenching: Cr15 steel hardening heat is at 820 ~ 860 DEG C, and oil quenching cut off diameter is 25mm, typically uses oil quenchinng, and the heating and thermal insulation time is longer than alloy tool steel, salt bath heating coefficient value 0.8 ~ 1.5min/mm, air furnace heating coefficient 1.5 ~ 2min/mm；

4) tempering: using the lonneal of 460 DEG C ± 10 DEG C, tempering time is generally 2 ~ 4h.