A kind of novel high alloy die steel and thermal treatment process thereof
Technical field
The present invention relates to a kind of novel alloy tool steel, relate in particular to a kind of novel high alloy die steel and thermal treatment process thereof.
Background technology
Compression molding has become production, especially the main processing means of household electrical appliances, daily necessities.The working conditions of mould reaches performance demands is varied, thereby selects different steel classes for use at different service conditions.Performance-the price of die steel is than being the parameter of weighing its economic benefit, and cold extrusion die also requires high as far as possible obdurability except that requiring the crushing resistance close with other cold-working moulds (being hardness).For processing the mould that high-strength material requires high life (big as far as possible punching press number of packages) simultaneously again, also need certain fatigue resistance.
The existing steel that is used for cold-work die generally adopts Cr
12Mo
1V
1Steel is made, and the composition of alloy is: C1.4~1.6%, Si0.6%, Mn0.6%, Cr11~13%, Co1%, V1.1%, Mo0.7~1.2%, S≤0.03%, P≤0.03%.This alloy when in use because toughness and processability are not fine, the pressure-bearing number of times of mould and the work-ing life of mould also reduce greatly.
Chinese invention patent (publication number is CN1116661) discloses the empty hard tool steel of a kind of little distortion, it is characterized in that carbon containing C1.00~1.10%, contain manganese Mn0.60~0.80%, siliceous Si0.50~0.70% contains chromium Cr3.70~4.20%, contains molybdenum Mo0.80~1.00%, contain vanadium V0.40~0.50%, sulfur-bearing S<0.02%, phosphorous P<0.02%, all the other are the content of iron Fe.Heat treatment deformation is atomic, annealing hardness HB200~220, air quenching hardness HRC58~62, the hardening capacity height, can extensively substitute oil quenching worker, die steel, be used for light cut and thin, long, thin cutting tool at a slow speed, cold-work die, model and roll etc., instrument and Mold Making process are simplified, high life.But this tool steel and Cr
12Mo
1V
1Steel is the same, all contains more high-load Mo, now owing to Mo on the world market lacks, and the price comparison costliness, the cost of therefore producing alloy is higher.
Chinese invention patent (publication number is CN1166533) discloses a kind of novel Ledeburite-less high-alloy cold-working die steel, its composition is: C0.4~1.4%, Cr7.0~10.0%, Mo1.0~2.0%, V2.0~8.0%, because carbon content is low, thus when the ingot casting condensation, do not form the Lai Shi eutectic, thereby do not have carbide segregation and thick carbide.About HRC55, textura epidermoidea and hardness and famous powder cold-work die steel V-4, V-10 are suitable through specific thermal treatment (comprising controlled no inner oxidation over-carburizing, low temperature quenching and low-temperaturetempering) back centre hardness.This steel alloy contains more high-load Mo, V equally, so production cost improves greatly.
It is C:0.5~0.65% that Chinese invention patent ZL02100041 discloses a kind of high-strength tough cold extruded die steel composition range, Cr:4.5~5.5%, Mo:1.0~2.0%, W:0.2~0.8%, V:0.40~0.80%, Si:0.30~0.60%, Mn≤0.40%, S.P≤0.30%, RE rare earth element≤0.30%, above numeral is weight percentage, and surplus is an iron.The advantage of this invention is: be used for (HRC57-62 divides two class) cold extruding die of Stainless Steel Watch Band element, watchcase etc. with quenching-Annealed Strip, mould is used homemade Cr than former
12The MoV mean lifetime increases.But this steel alloy contains more high-load Mo equally, so production cost is higher.
Summary of the invention
For the toughness, wear resistance and the processability that solve above-mentioned steel alloy bad, the technological deficiency that production cost is high.The purpose of this invention is to provide and a kind ofly also have enough toughness and wear resistance after quenching, hardening capacity is good, can make meticulous mould, long service life, the novel high alloy die steel that production cost is low.
Second purpose of the present invention provides the thermal treatment process of above-mentioned novel high alloy die steel.
In order to reach first above-mentioned goal of the invention, the present invention has adopted following technical scheme:
A kind of novel high alloy die steel, this die steel comprises by weight percentage: carbon C1.15~1.4%, chromium Cr10.8~12.3%, molybdenum Mo0.3~0.8%, vanadium V0.3~0.8%, nickel 0.1~0.3%, tungsten W0.2~1.0%, silicon Si0.1~0.4%, manganese Mn0.1~0.4%, sulphur S≤0.015%, phosphorus P≤0.02%, its surplus is iron Fe.
As preferably, this die steel comprises by weight percentage: carbon C1.25~1.35%, chromium Cr11.3~12.0%, molybdenum Mo0.4~0.6%, vanadium V0.4~0.6%, nickel 0.1~0.3%, tungsten W0.3~0.8%, silicon Si0.1~0.4%, manganese Mn0.1~0.4%, sulphur S≤0.015%, phosphorus P≤0.02%, its surplus is iron Fe.
As most preferably, this die steel comprises by weight percentage: carbon C1.3%, and chromium Cr11.5%, molybdenum Mo0.5%, vanadium V0.5%, nickel 0.2%, tungsten W0.5%, silicon Si0.2%, manganese Mn0.2%, sulphur S≤0.015%, phosphorus P≤0.02%, its surplus is iron Fe.
As preferably, this die steel also comprises: the niobium below 0.3%.
As preferably, this die steel also comprises: the titanium below 0.3%.
As preferably, this die steel also comprises: the rare earth element below 0.05%.
In order to realize second purpose of the present invention, the thermal treatment process of novel high alloy die steel of the present invention may further comprise the steps:
(1), for the first time preheat, pre-heating temperature is 550~650 ℃, and the time of preheating is 30~60 minutes;
(2), for the second time preheat, the secondary pre-heating temperature is 800~900 ℃, and the time of preheating is 30~60 minutes;
(3), the heating of quenching, quenching temperature is 980~1020 ℃, adopts the cooling of oil cooling or air cooling or salt bath;
(4), tempering, tempering temperature is 200~220 ℃, air cooling is to room temperature then.
As preferably, adopt the oil cooling cooling in the step (2), classification insulation in the oil cooling, holding temperature is 200~250 ℃.
As preferably, adopt salt bath cooling cooling in the step (2), classification insulation in the salt bath cooling, holding temperature is 400~450 ℃.
As preferably, after cooling off, tempering carries out temper once more.
What the main composition range of the present invention was determined the reasons are as follows:
Carbon, the various carbide that it and carbide forming element form are vital tissue factors that steel obtains hot strength.An amount of superfluous carbide can stop grain growth, improves wear resistance.But carbon content is too high, can make steel lose plasticity, because carbide is too much, skewness can cause that also mould bursts apart in addition.The suitable content of carbon of the present invention is 1.15~1.4%.
Silicon its objective is the hardening capacity, temper resistance and the matrix strength that improve steel, guarantees hot strength, hot hardness and the thermostability of steel, and the suitable content of silicon of the present invention is 0.1~0.4%.
Manganese its objective is the hardening capacity that improves steel, eliminates the harmful effect that sulphur exists simultaneously, and the suitable content of manganese of the present invention is 0.1~0.4%.
Chromium, main effect is hardening capacity and the oxidation-resistance that improves steel, and chromium is a kind of intensive carbide forming element, and it can form multiple compound with carbon, and forms the compound compound with iron carbon, but too high chromium content impairs the hot strength of steel.The suitable content of chromium of the present invention is 10.8~12.3%.
Vanadium, molybdenum, tungsten are the strong carbide forming element.Adding vanadium 0.3~0.8% can prevent the thermo-responsive tendency of mistake of steel, improves the hot hardness and the hot strength of steel.Add molybdenum Mo0.3~0.8% and can improve hardening capacity and heat resistance.Add tungsten 0.2~1.0% and play the effect that improves heat resistance.
Nickel is non-carbide forming element, improves the intensity of steel by the solution strengthening mode, and plasticity and toughness are also had improvement.Simultaneously, add the critical quenching rate that nickel can reduce steel, thereby the hardening capacity of steel is improved greatly.Chromium nickel coexists in the steel, can improve the comprehensive mechanical performance of steel greatly.The suitable content of nickel of the present invention is 0.1~0.3%.
Niobium, it is the carbide forming element also stronger than vanadium.A spot of niobium mainly exists with the form of niobium carbide in the steel.Can stop austenite crystal to be grown up, thereby improve toughness, improve hot worked processing performance.The present invention adopts the niobium below 0.3%.
Titanium can improve wear resisting property.The present invention adopts the titanium below 0.3%.
Rare earth, to the antioxidant property that improves alloy, tangible effect is arranged, in addition, rare earth also has directly and improves FATIGUE CRACK GROWTH.The present invention adopts the rare earth element below 0.05%.
Sulphur S of the present invention≤0.015%, phosphorus P≤0.02%, the purity height of steel alloy, the anti-fatigue performance of steel alloy and other mechanical propertys are all very good.
Alloy steel material of the present invention for molybdenum, has reduced the production cost of steel alloy with tungsten.Simultaneously, form wolfram varbide in a spot of tungsten adding steel, make steel have higher wear resistance.Adding a spot of nickel hardness when quenching can not be affected, and hardening capacity, wear resistance and the toughness of steel are improved greatly, under identical purity and equal grain fineness number, the comprehensive mechanical performance of steel improves more than 30%, can make meticulous mould, long service life, being a kind of more economical, more suitable, comprehensive raising cold-work die steel overall performance is played the novel steel grade of main effect, is the desirable moulding stock that is used to suppress watchcase, watchband.
Description of drawings
Fig. 1 is the novel high alloy die steel heat treatment cycle curve of the present invention figure.
Fig. 2 is the novel high alloy die steel tempering curve of the present invention figure.
Embodiment
Embodiment 1
A kind of novel high alloy die steel, this die steel comprises by weight percentage: carbon C1.3%, chromium Cr11.5%, molybdenum Mo0.5%, vanadium V0.5%, nickel 0.2%, tungsten W0.5%, silicon Si0.2%, manganese Mn0.2%, niobium 0.3%, titanium 0.3%, rare earth element 0.05%, sulphur S≤0.015%, phosphorus P≤0.02%, its surplus is iron Fe.
Above-mentioned novel high alloy die steel thermal treatment process, can adopt following steps to carry out:
(1), for the first time preheat, pre-heating temperature is 550~650 ℃, and the time of preheating is 60 minutes;
(2), for the second time preheat, the secondary pre-heating temperature is 800~900 ℃, and the time of preheating is 45 minutes;
(3), the heating of quenching, quenching temperature is 980~1020 ℃, the cool time is: 25+ material thickness/2 (minute), air cooling is to room temperature then;
(4), tempering for the first time, tempering temperature is 200~220 ℃, tempering time is 2.5 hours, air cooling is to room temperature then;
(5), tempering for the second time, tempering temperature is 200~220 ℃, tempering time is 2.5 hours, air cooling is to room temperature then.
Embodiment 2
A kind of novel high alloy die steel, this die steel comprises by weight percentage: carbon C1.25%, chromium Cr11.3%, molybdenum Mo0.4%, vanadium V0.4%, nickel 0.1%, tungsten W0.3%, silicon Si0.1%, manganese Mn0.1%, niobium 0.3%, titanium 0.3%, rare earth element 0.05%, sulphur S≤0.015%, phosphorus P≤0.02%, its surplus is iron Fe.
Above-mentioned novel high alloy die steel thermal treatment process, can adopt following steps to carry out:
(1), for the first time preheat, pre-heating temperature is 550~650 ℃, and the time of preheating is 60 minutes;
(2), for the second time preheat, the secondary pre-heating temperature is 800~900 ℃, and the time of preheating is 45 minutes;
(3), the heating of quenching, quenching temperature is 980~1020 ℃, the cool time is: 25+ material thickness/2 (minute), adopt the salt bath cooling then, classification insulation in the salt bath cooling, holding temperature is 400~450 ℃, is cooled to room temperature then;
(4), tempering for the first time, tempering temperature is 200~220 ℃, tempering time is 2.5 hours, air cooling is to room temperature then;
(5), tempering for the second time, tempering temperature is 200~220 ℃, tempering time is 2.5 hours, air cooling is to room temperature then.
Embodiment 3
A kind of novel high alloy die steel, this die steel comprises by weight percentage: carbon C1.35%, chromium Cr12.0%, molybdenum Mo0.6%, vanadium V0.6%, nickel 0.3%, tungsten W0.8%, silicon Si0.4%, manganese Mn0.4%, niobium 0.3%, titanium 0.3%, rare earth element 0.05%, sulphur S≤0.015%, phosphorus P≤0.02%, its surplus is iron Fe.
Above-mentioned novel high alloy die steel thermal treatment process, can adopt following steps to carry out:
(1), for the first time preheat, pre-heating temperature is 550~650 ℃, and the time of preheating is 60 minutes;
(2), for the second time preheat, the secondary pre-heating temperature is 800~900 ℃, and the time of preheating is 45 minutes;
(3), the heating of quenching, quenching temperature is 980~1020 ℃, the cool time is: 25+ material thickness/2 (minute), adopt the oil cooling cooling then, classification insulation in the oil cooling, holding temperature is 200~250 ℃;
(4), tempering for the first time, tempering temperature is 200~220 ℃, tempering time is 2.5 hours, air cooling is to room temperature then;
(5), tempering for the second time, tempering temperature is 200~220 ℃, tempering time is 2.5 hours, air cooling is to room temperature then.