CN103757181A - High-strength nut heat treatment technology - Google Patents

Abstract

The invention discloses a high-strength nut heat treatment technology which comprises the following steps: 1) preheating a to-be-treated nut for 3-4 hours with the preheating furnace temperature of 340-350 DEG C; 2) keeping warm in a salt bath furnace at 700-710 DEG C for 1-1.5 hours for quenching with a salt solution being a mixed solution of sodium chloride with a concentration of 100-120g / L, potassium chloride with a concentration of 130-140g / L, sodium sulfate with a concentration of 150-180g / L of and potassium nitrate with a concentration of 140-160g / L; 3) performing first stage quenching, using nitrate salt for isothermal quenching to 400-405 DEG C, wherein a nitrate salt quenching agent is a quenching agent with a mass ratio of potassium nitrate to sodium nitrate being 3:1; 4) performing second stage quenching, using hot water of 120-125 DEG C for quenching to 160-165 DEG C; 5) keeping warm in a tempering furnace of 400-405 DEG C for 1 to 2 hours, and then cooling by air to room temperature. According to the high-strength nut heat treatment technology, the treated nut is less in fracture surface shrinkage, high in cooperation rate and low in rejection rate, and the use of a cyanide impregnation agent harmful to human body and environment can be avoided.

Description

The thermal treatment process of high strength nut

Technical field

The present invention relates to the thermal treatment process of high strength nut.

Background technology

The thermal treatment process of the nut that requirement of strength is high conventionally adopts carburizing or cyaniding to add the techniques such as Q-tempering and processes, and 850-900 ℃ of annealing employing is also incubated 10 hours, but nut relative reduction in area when quenching becomes large, fit rate step-down, and scrap rate becomes greatly.

Summary of the invention

The object of the present invention is to provide a kind of thermal treatment process of high strength nut, the nut relative reduction in area of its processing is little, and fit rate is high, and scrap rate reduces, and avoids using human body and the harmful Cyanides penetration enhancer of environment.

For achieving the above object, technical scheme of the present invention is the thermal treatment process of a kind of high strength nut of design, comprises the steps:

1) by pending nut preheating 3-4 hour, preheating oven furnace temperature 340-350 ℃;

2) in the salt bath furnace of 700-710 ℃, be incubated 1-1.5 hour again and quench, saline solution adopts the mixing solutions of the saltpetre that sodium-chlor that concentration is 100-120g/L, Repone K that concentration is 130-140g/L, sodium sulfate that concentration is 150-180g/L and concentration are 140-160g/L;

3) first stage quenches, and adopts salt made from earth containing a comparatively high percentage of sodium chloride constant temperature to be quenched to 400-405 ℃, and described nitrate quenching agent is the quenching medium that saltpetre and SODIUMNITRATE are mixed by the mass ratio of 3:1;

4) subordinate phase is quenched, and adopts 120-125 ℃ of hot water to be quenched to 160-165 ℃;

5) in the tempering stove of 400-405 ℃, be incubated 1-2 hour again after air cooling to normal temperature.

Advantage of the present invention and beneficial effect are: a kind of thermal treatment process of high strength nut is provided, and the nut relative reduction in area of its processing is little, and fit rate is high, and scrap rate reduces, and avoid using human body and the harmful Cyanides penetration enhancer of environment.

Embodiment

Below in conjunction with embodiment, the specific embodiment of the present invention is further described.Following examples are only for technical scheme of the present invention is more clearly described, and can not limit the scope of the invention with this.

The concrete technical scheme of implementing of the present invention is:

Embodiment 1

A thermal treatment process for high strength nut, comprises the steps:

1) by pending nut preheating 4 hours, 350 ℃ of preheating oven furnace temperature;

2) in the salt bath furnace of 710 ℃, be incubated 1.5 hours again and quench, saline solution adopts the mixing solutions of the saltpetre that sodium-chlor that concentration is 120g/L, Repone K that concentration is 140g/L, sodium sulfate that concentration is 180g/L and concentration are 160g/L;

3) first stage quenches, and adopts salt made from earth containing a comparatively high percentage of sodium chloride constant temperature to be quenched to 405 ℃, and described nitrate quenching agent is the quenching medium that saltpetre and SODIUMNITRATE are mixed by the mass ratio of 3:1;

4) subordinate phase is quenched, and adopts 125 ℃ of hot water to be quenched to 165 ℃;

5) in the tempering stove of 405 ℃, be incubated 2 hours again after air cooling to normal temperature.

Embodiment 2

A thermal treatment process for high strength nut, comprises the steps:

1) by pending nut preheating 3 hours, 340 ℃ of preheating oven furnace temperature;

2) in the salt bath furnace of 700 ℃, be incubated 1 hour again and quench, saline solution adopts the mixing solutions of the saltpetre that sodium-chlor that concentration is 100g/L, Repone K that concentration is 130g/L, sodium sulfate that concentration is 150g/L and concentration are 140g/L;

3) first stage quenches, and adopts salt made from earth containing a comparatively high percentage of sodium chloride constant temperature to be quenched to 400 ℃, and described nitrate quenching agent is the quenching medium that saltpetre and SODIUMNITRATE are mixed by the mass ratio of 3:1;

4) subordinate phase is quenched, and adopts 120 ℃ of hot water to be quenched to 160 ℃;

5) in the tempering stove of 400 ℃, be incubated 1 hour again after air cooling to normal temperature.

Embodiment 3

A thermal treatment process for high strength nut, comprises the steps:

1) by pending nut preheating 3.5 hours, 344 ℃ of preheating oven furnace temperature;

2) in the salt bath furnace of 707 ℃, be incubated 1.2 hours again and quench, saline solution adopts the mixing solutions of the saltpetre that sodium-chlor that concentration is 108g/L, Repone K that concentration is 133g/L, sodium sulfate that concentration is 158g/L and concentration are 147g/L;

3) first stage quenches, and adopts salt made from earth containing a comparatively high percentage of sodium chloride constant temperature to be quenched to 403 ℃, and described nitrate quenching agent is the quenching medium that saltpetre and SODIUMNITRATE are mixed by the mass ratio of 3:1;

4) subordinate phase is quenched, and adopts 122 ℃ of hot water to be quenched to 164 ℃;

5) in the tempering stove of 404 ℃, be incubated 1.5 hours again after air cooling to normal temperature.

 

The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, do not departing under the prerequisite of the technology of the present invention principle; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (1)

1. the thermal treatment process of high strength nut, is characterized in that, comprises the steps:

1) by pending nut preheating 3-4 hour, preheating oven furnace temperature 340-350 ℃;

2) in the salt bath furnace of 700-710 ℃, be incubated 1-1.5 hour again and quench, saline solution adopts the mixing solutions of the saltpetre that sodium-chlor that concentration is 100-120g/L, Repone K that concentration is 130-140g/L, sodium sulfate that concentration is 150-180g/L and concentration are 140-160g/L;

3) first stage quenches, and adopts salt made from earth containing a comparatively high percentage of sodium chloride constant temperature to be quenched to 400-405 ℃, and described nitrate quenching agent is the quenching medium that saltpetre and SODIUMNITRATE are mixed by the mass ratio of 3:1;

4) subordinate phase is quenched, and adopts 120-125 ℃ of hot water to be quenched to 160-165 ℃;

5) in the tempering stove of 400-405 ℃, be incubated 1-2 hour again after air cooling to normal temperature.