CN103088349A - Heating processing technology for material of plunger of plunger pump - Google Patents

Abstract

The invention provides a heating processing technology for a material of a plunger of a plunger pump. The heating process comprises the following steps of: adopting an SCM420 alloy constructional steel, placing each raw material in a container to fill nitrogen so as to control the proportion of a carbon potential, heating to 900 DEG C, and carrying out heat preservation; and adjusting the carbon potential proportion so as to strongly seep and diffuse, lowering the temperature, carrying out heat preservation, quenching, carrying out tempering technology and discharging. The technology provided by the invention overcomes the shortage of the prior art, a friction auxiliary of the plunger and a plunger hole of a cylinder body is improved, the production efficiency is effectively improved, and the cost is reduced.

Description

A kind of ram pump thermal treatment process of the material of plunger

Technical field

The present invention relates to a kind of ram pump with the thermal treatment process of the material of plunger, belong to the engineering materials technical field.

Background technology

Ram pump is the strength member in hydraulic efficiency system, and effect is for system provides hydraulic energy, and its importance is equivalent to the heart in human body, must be constantly correctly, effectively, work reliably, and this also makes the design difficulty of ram pump increase.Wherein plunger as the core part of ram pump, requires it can bear high pressure, high temperature and certain impact, so require plunger surface to have high strength, high rigidity, high-wearing feature and certain center toughness.

At present, the most 31CrMoV9 of employing of the plunger that uses on high tonnage ram pump structural alloy steel carries out nitrogenize to be used, its advantage is can obtain excellent good comprehensive mechanical property after modified and nitrogenize, and nitrided case has good wear resistance, fatigue strength, has high-wearing feature.But the shortcomings such as it also has starting material and the thermal treatment cost is high, heat treatment time is long.

Summary of the invention

The technical problem to be solved in the present invention is to provide and a kind ofly can improves intensity, hardness and wear resisting property, and the ram pump of Cost reduction is with the thermal treatment process of the material of plunger simultaneously.

In order to solve the problems of the technologies described above, technical scheme of the present invention is to provide the thermal treatment process that a kind of ram pump is used the material of plunger, it is characterized in that: adopt the SCM420 structural alloy steel, concrete heat treatment step is as follows:

The first step: the temperature rise period, workpiece is placed in container, be filled with 38%～40% nitrogen, guarantee that the workpiece surface carbon potential is 0.5%～0.7%, make temperature reach 900～950 ℃ in 1min;

Second step: holding stage, temperature is controlled at 900～950 ℃ on the basis of the first step, be incubated 10～12 minutes;

The 3rd step: ooze the stage by force, on the basis of second step, carbon potential is increased to 1%, the rate of decomposition of carbon is controlled at 85%～88%, is incubated 10～12 minutes;

The 4th step: diffusion phase, on the basis in the 3rd step, carbon potential is adjusted to 0.9%, the rate of decomposition of carbon is controlled at 95%～97%, is incubated 10～12 minutes;

The 5th step: temperature-fall period, on the basis in the 4th step, carbon potential is adjusted to 0.8%, temperature is down to 750～800 ℃, is incubated 10～12 minutes;

The 6th step: holding stage is incubated 30～35 minutes on the basis in the 5th step;

The 7th step: the quenching stage, to quench with oil on the basis in the 6th step, quenching temperature is controlled at 800～870 ℃, and the time is 15～17 minutes;

The 8th step: the tempering stage, carry out tempering on the basis in the 7th step, tempering temperature is controlled at 180～200 ℃, and the time is 120～150 minutes; Come out of the stove.

A kind of ram pump provided by the invention replaces the 38CrMoAl structural alloy steel with the thermal treatment process of the material of plunger with the SCM420 structural alloy steel, takes special thermal treatment technique.Prove through sufficient commerical test, this process improving the friction pair of plunger and cylinder body plunger hole, can prevent the phenomenons such as plunger plucking, and can obtain surface and centre hardness and the hardened layer of design, effectively improve production efficiency, reduced cost.

Technique provided by the invention has overcome the deficiencies in the prior art, has improved the friction pair of plunger and cylinder body plunger hole, has effectively improved production efficiency, has reduced cost.

Description of drawings

Fig. 1 is the thermal treatment process figure that a kind of ram pump provided by the invention is used the material (SCM420) of plunger;

Fig. 2 is 38CrMoAl structural alloy steel and SCM420 hardness of structural alloy steel gradient map;

Fig. 3 is the thermal treatment process figure that traditional ram pump is used the material (31CrMoV9) of plunger.

Embodiment

For the present invention is become apparent, hereby with a preferred embodiment, and coordinate accompanying drawing to be described in detail below.

Fig. 1 is the thermal treatment process figure that a kind of ram pump provided by the invention is used the material (SCM420) of plunger, described thermal treatment process adopts the SCM420 structural alloy steel to replace 38CrMoAl, require carburizing and quenching, surface hardness 60～64HRC, carburized layer depth 0.3～0.6mm, centre hardness 37～45HRC.Concrete heat treatment step is as follows:

The first step: the temperature rise period, workpiece is placed in container, be filled with 38%～40% nitrogen, guarantee that the workpiece surface carbon potential is 0.5%～0.7%, make temperature reach 900～950 ℃ in 1min;

Second step: holding stage, temperature is controlled at 900～950 ℃ on the basis of the first step, be incubated 10～12 minutes;

The 3rd step: ooze the stage by force, on the basis of second step, carbon potential is increased to 1%, the rate of decomposition of carbon is controlled at 85%～88%, is incubated 10～12 minutes;

The 4th step: diffusion phase, on the basis in the 3rd step, carbon potential is adjusted to 0.9%, the rate of decomposition of carbon is controlled at 95%～97%, is incubated 10～12 minutes;

The 5th step: temperature-fall period, on the basis in the 4th step, carbon potential is adjusted to 0.8%, temperature is down to 750～800 ℃, is incubated 10～12 minutes;

The 6th step: holding stage is incubated 30～35 minutes on the basis in the 5th step;

The 7th step: the quenching stage, to quench with oil on the basis in the 6th step, quenching temperature is controlled at 800～870 ℃, and the time is 15～17 minutes;

The 8th step: the tempering stage, carry out tempering on the basis in the 7th step, tempering temperature is controlled at 180～200 ℃, and the time is 120～150 minutes; Come out of the stove.

Figure 3 shows that traditional ram pump thermal treatment process figure of the material (31CrMoV9) of plunger, the concrete steps of its thermal treatment process are:

The first step: workpiece is placed in container, after container vacuum-pumping, is filled with nitrogen;

Second step: the mixture heating up to 510 that the first step is obtained ℃, be incubated 25 hours, ammonia decomposition 18%～25%, ammonia flow is 3Nm ³/ h;

The 3rd step: the mixture heating up to 550 that the fs obtains second step ℃, be incubated 25 hours, ammonia decomposition 50%～60%, ammonia flow is 5Nm ³/ h; Subordinate phase is incubated 2 hours again on the fs basis, ammonia decomposition＞80%, ammonia flow are 3Nm ³/ h;

The 4th step: the mixture that the 3rd step obtained, is come out of the stove after 20 minutes 80 ℃ of insulations.

Elemental composition contrast list when using SCM420 structural alloy steel and 38CrMoAl structural alloy steel, as shown in table 1:

Elemental composition contrast when table 1 uses SCM420 and 38CrMoAl

Composition (wt%)

C

Si

Mn

Cr

Mo

V

Fe

SCM420

0.18～0.23

0.15～0.35

0.6～0.9

0.9～1.2

-

-

Surplus

38CrMoAl

0.27～0.34

＜0.4

0.4～0.7

2.3～2.7

0.15～0.25

0.1～0.2

Surplus

The hardness of the plungers pump plunger made from 0.3kg power test technique provided by the invention and traditional technology by the GB/11354 testing standard, hardness gradient contrasts as shown in Figure 2.As shown in Figure 2, adopt surface hardness, case depth, the centre hardness of the plungers pump plunger that ram pump provided by the invention makes with the thermal treatment process of the material of plunger all to meet the requirements.

With technique provided by the invention and traditional technology make material be processed into plunger part by drawing respectively, be assembled on ram pump, compare test by following condition: first carry out performance test in 5 hours on the integrated hydraulic testing table, refill and carry out strenuous test in 200 hours on same excavator complete machine, after strenuous test in 200 hours, the surface white bright spot (nitride layer comes off) occurs and cut is arranged by the plunger of 38CrMoAl structural alloy steel materials processing; After strenuous test in 200 hours, part does not have wear phenomenon by the plunger of SCM420 structural alloy steel materials processing.Illustrate that the plunger of SCM420 alloy structure steel making and the friction pair that cylinder body (nitriding treatment) forms are more desirable, thus the work-ing life of having improved ram pump.

Because the present invention takes new material, and adopt new thermal treatment process, the holistic cost comparison Comparative Examples that machines from the materials procurement to the part has reduced by 30%.

Claims (1)

1. a ram pump is with the thermal treatment process of the material of plunger, and it is characterized in that: adopt the SCM420 structural alloy steel, concrete heat treatment step is as follows:

The first step: the temperature rise period, workpiece is placed in container, be filled with 38%～40% nitrogen, guarantee that the workpiece surface carbon potential is 0.5%～0.7%, make temperature reach 900～950 ℃ in 1min;

Second step: holding stage, temperature is controlled at 900～950 ℃ on the basis of the first step, be incubated 10～12 minutes;

The 3rd step: ooze the stage by force, on the basis of second step, carbon potential is increased to 1%, the rate of decomposition of carbon is controlled at 85%～88%, is incubated 10～12 minutes;

The 4th step: diffusion phase, on the basis in the 3rd step, carbon potential is adjusted to 0.9%, the rate of decomposition of carbon is controlled at 95%～97%, is incubated 10～12 minutes;

The 5th step: temperature-fall period, on the basis in the 4th step, carbon potential is adjusted to 0.8%, temperature is down to 750～800 ℃, is incubated 10～12 minutes;

The 6th step: holding stage is incubated 30～35 minutes on the basis in the 5th step;

The 7th step: the quenching stage, to quench with oil on the basis in the 6th step, quenching temperature is controlled at 800～870 ℃, and the time is 15～17 minutes;

The 8th step: the tempering stage, carry out tempering on the basis in the 7th step, tempering temperature is controlled at 180～200 ℃, and the time is 120～150 minutes; Come out of the stove.

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