CN105063328A - DZ1 axle heat treatment technique - Google Patents

Abstract

The invention provides a DZ1 1 axle heat treatment technique, relating to the technical field of treatment techniques of motor train unit axles. The heat treatment technique comprises the following steps: carrying out primary normalizing, secondary normalizing, quenching and tempering on the axle to complete the heat treatment on the DZ1 axle. The heat treatment technique can be utilized to produce the acceptable axle product which satisfies the specifications in [2013]49 200-250km/h Motor Train Unit Axle Trial Technical Conditions (Temporary), and fills up the blank in the national DZ1 axle heat treatment technique.

Description

DZ1 axletree thermal treatment process

Technical field

The present invention relates to motor train unit train axletree treatment process technical field, be specifically related to a kind of DZ1 axletree thermal treatment process.

Background technology

Motor train unit train axletree is very important parts in EMUs EEF bogie, but the CRH1 that China runs now, CRH2, what CRH3 and CRH5 type motor train unit shaft material all adopted is imported materials and items, major part adopts steel alloy, and train of high-speed motor train unit axletree standard is also adopt external relevant criterion.

In order to accelerate the progress of motor train unit accessory technology production domesticization, in August, 2012, taken the lead by Metals & Chemistry Research Institute, integrated steel mill and axletree production unit have carried out subject study to axle of motor train unit technological standard, and have issued No. [2013] 49, scientific and technological dress letter " speed per hour 200 ~ 250 kilometer motor vehicle group axletree trial-manufacture technology condition (provisional) " in September, 2013.

Axletree Main Mechanical index in " speed per hour 200-250 kilometer motor vehicle group axletree trial-manufacture technology condition (provisional) " after thermal treatment is as follows:

The metallographic structure of thermal treatment axletree is the ferritic structure of bainite+martensitic tempered structure and a small amount of (being not more than 5%), and should be shown as uniform fine grain structure in whole detection faces, and grain fineness number should be not less than 6 grades, is differentially less than 2 grades.

The material great majority of current overseas high speed EMUs axle steel adopt EA4T, and perform European standard EN13261, thermal treatment process is quenching+high tempering (modified).EA4T axle steel thermal treatment process is adopted to carry out technological test to DZ1 material axletree, test-results can not meet " speed per hour 200-250 kilometer motor vehicle group axletree trial-manufacture technology condition (provisional) ", in metallographic structure after axletree thermal treatment, ferrite content is greater than 5%, overproof.

Summary of the invention

In order to solve prior art exist axletree thermal treatment after cause the underproof technical problem of product because ferrite content is higher, the invention provides a kind of DZ1 axletree thermal treatment process.

The technical scheme that technical solution problem of the present invention is taked is as follows:

DZ1 axletree thermal treatment process, comprises the steps:

The first step, temperature is put into the continuous normalizing furnace of stepped start-stop system lower than the axletree of 500 DEG C, a normalizing and secondary normalizing process are carried out to axletree, one time normalizing holding temperature is 880 DEG C ± 10 DEG C, soaking time is 3.6 ~ 4.0h, secondary normalizing holding temperature 790 DEG C ± 10 DEG C, soaking time is 3.6 ~ 4.0h, and step duration is 9 minutes, and axletree carries out forced air cooling process after coming out of the stove;

Second step, the temperature after the first step process is put into well formula gas heating furnace lower than the axletree of 200 DEG C, every stove dress number of axle is not more than 6, carry out Quench heating process to axletree, quenching and preserving heat temperature is 890 DEG C ± 10 DEG C, and soaking time is 4.5 ~ 5.0h; Put into tank water-cooled after axletree Quench heating completes fast 30 minutes, in Cooling Process, axletree needs to swing, and cooling tank water temperature controls at 15 ~ 40 DEG C;

3rd step, the temperature after second step process is put into electric pit-type heating furnace lower than the axletree of 200 DEG C, every stove dress number of axle is not more than 6, and carry out tempering heat treated to axletree, tempering holding temperature is 650 DEG C ± 10 DEG C, and soaking time is 6 ~ 6.5h; Axletree tempering has been heated rear employing air cooling mode and has been carried out cooling process, and then completes DZ1 axletree thermal treatment process.

The invention has the beneficial effects as follows: the qualified axletree product meeting science and technology dress No. [2013] 49, letter " speed per hour 200 ~ 250 kilometer motor vehicle group axletree trial-manufacture technology condition (provisional) " and specify can be produced by this thermal treatment process, fill up the blank of domestic DZ1 material axletree thermal treatment process, lay a good foundation for my company enters axle of motor train unit market, also for the production domesticization of motor train unit accessory product is laid a good foundation.

Embodiment

Below in conjunction with embodiment, the present invention is described in further details.

DZ1 axletree thermal treatment process of the present invention comprises the steps:

The first step, temperature is put into the continuous normalizing furnace of stepped start-stop system lower than the axletree of 500 DEG C, a normalizing and secondary normalizing process are carried out to axletree, one time normalizing holding temperature is 880 DEG C ± 10 DEG C, soaking time is 3.6 ~ 4.0h, secondary normalizing holding temperature 790 DEG C ± 10 DEG C, soaking time is 3.6 ~ 4.0h, and step duration is 9 minutes, and axletree carries out forced air cooling process after coming out of the stove;

Second step, the temperature after the first step process is put into well formula gas heating furnace lower than the axletree of 200 DEG C, every stove dress number of axle is not more than 6, carry out Quench heating process to axletree, quenching and preserving heat temperature is 890 DEG C ± 10 DEG C, and soaking time is 4.5 ~ 5.0h; Put into tank water-cooled after axletree Quench heating completes fast 30 minutes, in Cooling Process, axletree needs to swing, and cooling tank water temperature controls at 15 ~ 40 DEG C;

3rd step, the temperature after second step process is put into electric pit-type heating furnace lower than the axletree of 200 DEG C, every stove dress number of axle is not more than 6, and carry out tempering heat treated to axletree, tempering holding temperature is 650 DEG C ± 10 DEG C, and soaking time is 6 ~ 6.5h; Axletree tempering has been heated rear employing air cooling mode and has been carried out cooling process, and then completes DZ1 axletree thermal treatment process.

Adopt thermal treatment process of the present invention, will by the full special steel in north, Taiyuan Iron and Steel Co., the CRH3 type axle of motor train unit volume that the blank of Ma Gangsan producer is forged is a stove, carry out same furnace treatment reason, then three producer's blank axletrees are all sampled and carried out test load-efficiency, test-results shows: the mechanical property of three producer's blank axletrees, metallographic structure and grain fineness number all meet the requirement of science and technology dress No. [2013] 49, letter " speed per hour 200 ~ 250 kilometer motor vehicle group axletree trial-manufacture technology condition (provisional) ", the underproof difficult problem of product is caused because ferrite content is higher after successfully solving axletree thermal treatment.

Claims (1)

1.DZ1 axletree thermal treatment process, is characterized in that, this technique comprises the steps:

The first step, temperature is put into the continuous normalizing furnace of stepped start-stop system lower than the axletree of 500 DEG C, a normalizing and secondary normalizing process are carried out to axletree, one time normalizing holding temperature is 880 DEG C ± 10 DEG C, soaking time is 3.6 ~ 4.0h, secondary normalizing holding temperature 790 DEG C ± 10 DEG C, soaking time is 3.6 ~ 4.0h, and step duration is 9 minutes, and axletree carries out forced air cooling process after coming out of the stove;

Second step, the temperature after the first step process is put into well formula gas heating furnace lower than the axletree of 200 DEG C, every stove dress number of axle is not more than 6, carry out Quench heating process to axletree, quenching and preserving heat temperature is 890 DEG C ± 10 DEG C, and soaking time is 4.5 ~ 5.0h; Put into tank water-cooled after axletree Quench heating completes fast 30 minutes, in Cooling Process, axletree needs to swing, and cooling tank water temperature controls at 15 ~ 40 DEG C;

3rd step, the temperature after second step process is put into electric pit-type heating furnace lower than the axletree of 200 DEG C, every stove dress number of axle is not more than 6, and carry out tempering heat treated to axletree, tempering holding temperature is 650 DEG C ± 10 DEG C, and soaking time is 6 ~ 6.5h; Axletree tempering has been heated rear employing air cooling mode and has been carried out cooling process, and then completes DZ1 axletree thermal treatment process.