Quenching/subzero treatment method for heat treatment of low-temperature nickel steel

Quenching/subzero treatment method for heat treatment of low-temperature nickel steel

  • CN 103,343,202 A
  • Filed: 07/11/2013
  • Published: 10/09/2013
  • Est. Priority Date: 07/11/2013
  • Status: Active Application
First Claim
Patent Images

1. low temperature nickel Heat Treatment Of Steel quenching cryogenic treating process, it is characterized in that:

  • the chemical substance material of use is;

    9Ni low-temperature steel, liquid nitrogen, water coolant, it is as follows that it prepares consumption;

    be measure unit with millimeter, milliliter9Ni low-temperature steel;

    9Ni 500mm * 500mm * 10mmLiquid nitrogen;

    N 2500000mL ±

    100mL Water coolant;

    H 2O 500000mL ±

    100mL Heat-treatment quenching, cryogenic treating process are as follows;

    (1) quenchesThe quenching heating of 9Ni low-temperature steel is carried out in the normalizing quenching furnance, finishes in the water-cooled process;

    Open normalizing quenching furnance and heating, be heated to temperature 820-840 ℃

    ;

    2. 9Ni low temperature steel plate is vertically placed the normalizing quenching furnance, and airtight, constant temperature insulation 40min;

    3. water coolant 500000mL ±

    100mL is added in the tank, the steel plate after quenching is put into tank fast, and flood whole steel plate, carry out chilling, chilling period 30min;

    (2) high temperingHigh tempering carries out in tempering stove, finishes in the heating process of cooling;

    1. open tempering stove and heating, be heated to temperature 540-560 ℃

    ;

    2. cooled steel plate is put into tempering stove, carry out high tempering, tempering time 50min;

    3. the steel plate behind the high tempering is taken out and place air, make it naturally cool to 25 ℃

    ;

    (3) liquid nitrogen precooling treatmentThe precooling treatment of liquid nitrogen is carried out in liquid nitrogen tank, is to lift in the process fast to finish in liquid nitrogen tank1. liquid nitrogen 500000mL is placed liquid nitrogen tank, and steady temperature-196 ℃

    ;

    2. steel plate is placed pail, the pail that steel plate will be housed then places liquid nitrogen, and lifts fast, and time 20min has namely finished precooling;

    (4) liquid nitrogen deep is handled1. the slow vertical lifting of the steel plate after the precooling treatment is put into liquid nitrogen tank, liquid nitrogen floods whole steel plate, and produces bubble, carries out sub-zero treatment, and steady temperature-196 ℃

    ;

    2. liquid nitrogen deep treatment time 30-40min;

    3. rise again, liquid nitrogen deep after handling is pulled steel plate out, place on the frame of rising again, and the time 20-30min that rises again, the back steel plate of rising again returns to 25 ℃

    ;

    4. sub-zero treatment repeats four times;

    (5) low-temperaturetempering is eliminated internal stressLow-temperaturetempering is carried out in tempering stove, finishes in the heating process of cooling;

    1. open tempering stove and heating, 100 ℃

    of Heating temperatures;

    2. steel plate is placed tempering stove, and airtight, soaking time 60min;

    3. after the tempering, close well heater, make steel plate naturally cool to 25 ℃

    with stove;

    4. take out steel plate after the tempering, be the low temperature nickel steel plate of quenching, sub-zero treatment;

    (6) detect, analyze, characterizeLow temperature nickel steel plate to quenching, sub-zero treatment detects, analyzes, characterizes;

    Carry out hardness test with Rockwell hardometer;

    Carry out toughness test with shock-testing machine;

    Make a strength test with tensile testing machine;

    Conclusion;

    the low temperature nickel steel plate Rockwell hardness of quenching, sub-zero treatment reaches HRC 31-33, and yield strength reaches 695-705MPa, and tensile strength reaches 750-760MPa, and low-temperature impact work reaches 250-260J.

View all claims
    ×
    ×

    Thank you for your feedback

    ×
    ×