CN101250668A - Hot work die steel - Google Patents

Abstract

The invention relates to a hot work die steel, which belongs to the technical field of material, wherein the components and mass percentage are that C 0.36-0.44, Si 0.25-0.50, Mn 0.20-0.80, P<=0.030, S<=0.030, Cr 3.00-4.00, Mo 1.60-2.20, W 1.50-2.00, V 0.80-1.50, Co 0.50-1.50, and the allowance is Fe. Utilization harness of the steel after thermal treatment is 45-52HRC, which has high fire-resisting property and proper toughness support, and is suitable for being used as a hot work die under the temperature which is over 600 DEG C to 700 DEG C.

Description

Hot-work die steel

Technical field

The present invention relates to a kind of steel alloy of metallic substance technical field, specifically is a kind of hot-work die steel.

Background technology

The present widely used grade of steel of hot-work die steel is H13, GB/T1299-2000 grade of steel 4Cr5MoSiV1, and the H13 steel of ASTM standard is introduced in equivalence.It is tough has both, and good thermal fatigue resistance and thermostability are arranged.The working condition that hot-work die steel is on active service is quite complicated, when use temperature surpasses 600 ℃, H13 will be because the thermotolerance deficiency will lose original premium properties, and the 3Cr2W8V steel of high heat resistance is bad because of poor toughness, thermal fatigue resistance again, and mould often chaps and early failure.Improve the H13 steel thermotolerance, to improve its use temperature when keeping its obdurability be present main task.

Find through literature search, improve the existing several ways of thermotolerance of H13 steel prior art: the one, interpolation 1%Al etc. are to improve the performance of steel.Authorized in 2004 patent of invention---application number 00117148.8 is exactly that H13+1%Al (add 0.3%Nb in addition and do not talk enforcement) is used for Al section bar hot-extrusion mold, mainly by improving surface nitride layer, improved the anti-melting loss performance of steel by a relatively large margin, the contriver infers except that hot extrude, also adapts to injection moulding and forge hot.

Second approach is to adjust H13 Chemical Composition and optimization production technology.The invention disclosed patent 200610116358.6, and its Chemical Composition is characterised in that carbon ratio H13 is low about 15%, makes alloying element without Si, and it is about 25% to reduce Cr, improves Mo about 60% and also adds the effect that further replenishes Mo above 1%W.Disclosed correlation data shows that 600 ℃ of temper number values are higher by 5% than H13, and its 600 ℃ of temper resistances are obviously than H13 height, and its good toughness.This steel is tough to be had both, and thermotolerance is better than H13, but shortage＞600-700 ℃ description and data.

Belong to commercial 8418 steel (Sweden) of this approach abroad, 1.2367 steel (Germany), show similar composition adjustment still difficulty be applicable to＞600-650 ℃ use temperature occasion.

Three approach is to add The addition of C o, W, Mo.

Document announcement is abroad arranged, to containing the Al injection moulding of Sil%, the Al liquid temp reaches 750 ℃, because heat resistanceheat resistant melting loss and thermotolerance require high, H13 type, 8418 types all do not meet the demands, and particularly point out that to contain the cobalt mass percent be that 4 H19-4Cr4W4MoV2Co4 is applicable to that hot melt decreases than the prior occasion of toughness.

Summary of the invention

The present invention is directed to the deficiencies in the prior art, a kind of hot-work die steel is provided, make its hardness reach 52HRC, have high thermotolerance appropriate toughness support is arranged again, do hot-work die under being fit to surpass 600 ℃ to 700 ℃ and use.

The present invention is achieved by the following technical solutions, hot-work die steel of the present invention, and component that comprises and mass percent thereof are:

C：0.36-0.44 Si：0.25-0.50 Mn：0.20-0.80

P：≤0.030 S：≤0.030 Cr：3.00-4.00

Mo：1.60-2.20 W：1.50-2.00 V：0.80-1.50

The Co:0.50-1.50 surplus is Fe.

Said components mass percent preferable range of the present invention is:

C：0.36-0.42 Si：0.25-0.50 Mn：0.40-0.80

P：≤0.020 S：≤0.012 Cr：3.20-3.80

Mo：1.60-2.00 W：1.50-1.80 V：0.80-1.20

The Co:0.50-1.00 surplus is Fe.

The present invention presses H13 technology and flow preparation.

Design considerations of the present invention is:

C: comprehensive mechanical property is good, generally is medium carbon steel.With the H13 carbon content is base, emphasizes high tenacity and the high tough carbon amount on the low side of selecting, and emphasizes to improve as far as possible under enough toughness supports heat resistance and should select higher carbon amount.Carbon amount 0.36-0.44% of the present invention is the middle upper limit of H13, and the carbon amount 0.30-0.36% of proper and open patent of invention 200610116358.6 forms linking.

Cr: be hardening capacity and the important assurance that high tenacity is arranged under 40-50HRC hardness.Requiring to improve as far as possible under the situation of heat resistance,, vanadium carbide is being separated out inhibition, can reduce the heat resistance of steel, the 5%Cr of H13 is being reduced to 3-4%, reduction amplitude 25% because Cr forms high chromium carbide.

Mo and W: all be the strong carbide forming element, can improve hot strength and thermostability.The two action compensating, the collocation result of use is good.It is 2.7 suitable with patent 200610116358.6 that Mo+1/1.8W of the present invention reaches.(H13 is 1.5)

V: be stronger carbide forming element, the carbide hardness of vanadium is the highest, and the tiny distribution disperse of particle promotes the age hardening effect and the anti-temper softening ability of steel effectively, thereby improves thermotolerance, add～1%, identical with the H13 steel.

Co: cobalt is non-carbide forming element, is fused to matrix, can hinder grain growth; Be fused to carbide, can improve the stability of carbide, all help the thermotolerance of steel to improve.But Co can make toughness worsen, and adds so choosing is a small amount of.Add-on of the present invention is 0.5-1.5%, is at half than H19.

Si: also be non-carbide forming element, under the condition that requires hot operation tool high heat-intensity, effects such as Si reinforcement matrix have disappeared, promote negative impact emersions such as decarburization, generally do not make alloying element separately and use.

Compared with prior art, the present invention is by adjusting the H13 Chemical Composition and adding the cobalt that is not more than mass percent 1.5, acquisition has the high hot heat-flash of appropriate toughness support to make die steel, this steel hardness of using after heat treatment is 45-52HRC, have high thermotolerance appropriate toughness support is arranged again, do hot-work die under being fit to surpass 600 ℃ to 700 ℃ and use.

Embodiment

Below embodiments of the invention are elaborated: present embodiment is being to implement under the prerequisite with the technical solution of the present invention, provided detailed embodiment and concrete operating process, but protection scope of the present invention is not limited to following embodiment.

Embodiment 1: the Φ 142mm round steel that strips off the skin

1, smelt the steel alloy of pressing present embodiment, the mass percent of its component is:

C：0.42 Si：0.48 Mn：0.22 P：0.021 S：0.020

Cr:3.80 Mo:1.98 W:1.80 V:1.18 Co:0.99 surplus is Fe.

2, induction furnace is smelted and is added the electroslag remelting.Smelt cast Φ 130mm electrode bar, esr becomes 850kg steel ingot and annealing, and technology is pressed the H13 current technology and carried out.

3, forge by the cogging of H13 technology and become Φ 150mm casting skin material, slow cooling annealing.

4, rough turn one-tenth Φ 142mm finished product, quality test qualified (containing internal soundness, surface quality and tolerance of dimension).

Embodiment 2: forge hot module steel 160mm * 220mm * 325mm

1, smelt the steel alloy of pressing present embodiment, the mass percent of its component is:

C：0.44Si：0.31Mn：0.75P：0.020S：0.010

The Cr:3.96Mo:2.18W:1.97V:1.49Co:1.47 surplus is Fe.

2, induction furnace is smelted and is added the electroslag remelting.Smelt cast Φ 130mm electrode bar, esr becomes 850kg steel ingot and annealing, and technology is pressed the H13 current technology and carried out.

3, forging is opened 210 square billets by H13 technology, and base slow cooling reconditioning is also qualified through UT (Ultrasonic Testing), and reheat also is swaged into 160mm * 220mm band steel, earnestly becomes the mould base.

4, the mould base is after machining and being heat-treated to 48HRC, about 9,000 times of work-ing life.

Embodiment 3: forge hot module 135mm * 135mm * 230mm

1. smelt the steel alloy of pressing present embodiment, the mass percent of its component is:

C：0.37 Si：0.32 Mn：0.53 P：0.018 S：0.010

Cr:3.43 Mo:1.92 W:1.56 V:0.83 Co:0.92 surplus is Fe.

2. induction furnace is smelted and is added the electroslag remelting.Smelt cast Φ 130mm electrode bar, esr becomes 850kg steel ingot and annealing, and technology is pressed the H13 current technology and carried out.

3. forging cogging: ESR ingot is split into 210 square billets by H13 technology.Be cut into the module base after the slow cooling annealing.

4. module forging: adopt upsetting pull technology to improve the module homogeneity of structure, vertically jumping-up laterally pulls out the end face levelling.

5. module is through annealing, and ultrasonic inspection etc. are up to the standards.

6. (molding) machining---temper of quenching meets the requirements of 47 ± 1HRC---is finish-machined to mould.

7. (use) stamp work to be auto parts, be heated to～1200 ℃ after forging, per minute is swaged into 15, the part mold clearing temperature is above 1000 ℃, about 1 minute of die clearance time, with the lubricated cooling of holding concurrently of meal, the working condition requirement moulding stock has high anti-temper resistance and thermotolerance under appropriate toughness support.

8. the steel alloy of present embodiment reaches 10,000 times work-ing life, and is high 1.3 ten thousand times, satisfies service requirements.

Embodiment 4: wrench hot-forging die base 110mm * 110mm * 280mm

1. the component and the mass percent thereof that comprise of present embodiment is:

C：0.42 Si：0.47 Mn：0.61 P：0.023 S：0.010

Cr:3.78 Mo:1.96 W:1.79 V:1.19 Co:0.98 surplus is Fe.

2. induction furnace is smelted and is added the electroslag remelting.Smelt the cast electrode bar, esr becomes 850kg steel ingot and annealing, forges forge hot and becomes 210 square billets, and base slow cooling reconditioning is also qualified through ultrasonic inspection, and reheat also is swaged into 110 * 110 square steel, earnestly becomes slow cooling behind the mould base, annealing. and technology press the execution of H13 current technology.

3. the mould base is through machining and be heat-treated to 52.1HRC, forges through examination repeatedly, and the life-span is stabilized in more than 4,000 times, and the user is satisfied with.Former extremely unstable with the 3Cr2W8V life-span.

Embodiment 5: roller stock Φ 125 * 1250 in the middle of the cluster mill

1. the component and the mass percent thereof that comprise of present embodiment is:

C：0.36 Si：0.26 Mn：0.39 P：0.019 S：0.017

Cr:3.02 Mo:1.62 W:1.51 V:0.83 Co:0.51 surplus is Fe.

2. induction furnace is smelted and is added the electroslag remelting.Smelt the cast electrode bar, esr becomes 1500kg steel ingot and annealing, and technology is pressed the H13 current technology and carried out.

3. forge and press the cogging of H13 technology, and become Φ 125 scale materials, slow cooling annealing.

After the roughing roller stock after quick all refinement thermal treatment, the integral body tempering of quenching again, hardness press 50-52HRC and is controlled.

5. intermediate roll can normally use smoothly by on probation.

Claims (2)

1. a hot-work die steel is characterized in that, component that comprises and mass percent thereof are:

C：0.36-0.44 Si：0.25-0.50 Mn：0.20-0.80

P：≤0.030 S：≤0.030 Cr：3.00-4.00

Mo：1.60-2.20 W：1.50-2.00 V.：0.80-1.50

The Co:0.50-1.50 surplus is Fe.

2. hot-work die steel according to claim 1 is characterized in that, component that comprises and mass percent thereof are:

C：0.36-0.42 Si：0.25-0.50 Mn：0.40-0.80

P：≤0.020 S：≤0.012 Cr：3.20-3.80

Mo：1.60-2.00 W：1.50-1.80 V：0.80-1.20

The Co:0.50-1.00 surplus is Fe.