CN1118381A

CN1118381A - High strength heat-resistance steel

Info

Publication number: CN1118381A
Application number: CN 95108211
Authority: CN
Inventors: 程世长; 林肇杰; 刘正东; 李密
Original assignee: Central Iron and Steel Research Institute
Current assignee: Central Iron and Steel Research Institute
Priority date: 1995-07-19
Filing date: 1995-07-19
Publication date: 1996-03-13
Anticipated expiration: 2015-07-19
Also published as: CN1034819C

Abstract

The high-strength refractory steel for gas valve in IC engine contains such chemical components (Wt.%) as C(0.02-0.2), Si (0.1-1.5), Mn (0.4-1.5), Cr (17-23), Ni (20-28), Al (0.7-2.0), Ti (1.8-3.2), Nb (0.7-2.0), Zr (0.01-0.2), Ce (0.003-0.1), Co (0.1-3.0), Cu (0.05-0.5) and Fe (residual) and features enough high-temp. strength and hardness and good antioxidation and anticorrosion nature.

Description

A kind of high strength heat resistant steel

The invention belongs to field of alloy steel.Mainly be applicable to intake valve and vent valve, diesel engine settling chamber nozzle and the abaculus etc. of oil engine.

Oil engine comprises petrol motor and diesel engine, is important power machine, and is of many uses, can be used for automobile, tractor, mixed boat, naval vessel, armoring tank, locomotive, generating set or the like.Air valve, nozzle, abaculus etc. are the vital parts of oil engine, are again attrition components simultaneously.In order to improve the power of oil engine, improve rotating speed often, reach 1000～2000 rev/mins usually as the high-speed diesel engine rotating speed, petrol motor is generally 2000～4000 rev/mins.Under high-revolving working conditions, air valve is done motion repeatedly with high frequency, contacts and opens with causing air valve and valve seat high frequency.In this process, air valve produces impact force (power of taking a seat) to valve seat, causes the corrosion of frictional wear and high-temperature fuel gas, and simultaneously, the spray orifice of nozzle and abaculus also is subjected to washing away of high-speed fuel gas.For this reason, air valve, nozzle and abaculus material as oil engine not only will have higher high temperature strength and hot hardness, but also require to have excellent anti-oxidant and anti-exhaust gas corrosion performance.

In the prior art, the selection of high loading Diesel Engine's Air Valve etc. has two kinds of schemes: a kind of is to select nickel-base alloy for use, as Inconel751 (HEV3) and Ninmonic80A (HEV5) (USS SAE J775), NiCr20TiAl (German standard DIN17480-1984), the excellent performance of this class alloy, production technique is simple, and its shortcoming is the cost height; Another kind of scheme is to be that matrix is made air valve with high temperature steel, and built-up welding one deck antifriction anticorrosion alloy on its conical surface then is as at 4Cr ₁₄Ni ₁₄W ₂Built-up welding one deck Stellite6 cobalt base alloy produces on the made air valve matrix conical surface of Mo steel or 21-12N steel, though this scheme can reach certain effect, also reduced cost, but having some shortcomings, mainly is complex manufacturing, and product is easy to generate defective, not only yield rate is low, and fragile when using, the life-span is low, also may cause burst accident (" rolling stock communication " 1994.No.4).

U.S. Pat 3420660 also provides a kind of high strength heat resistant steel.This steel not only contains Ni 20%, Cr 16%, Co 5.20～20.58% on chemical ingredients, but also contain W, Mo, Nb, V reach more than 3%, also contain Ti, Al and B simultaneously.Be a high quality steel, have very high intensity, but hot workability be poor, the plasticity and the toughness of steel are relatively poor, and the cost height.Mainly be applicable to heavily stressed member, as jet engine and steam turbine member.

The object of the present invention is to provide a kind of existing higher high temperature strength and hardness, excellent anti-oxidant and anti-exhaust gas corrosion performance and high strength heat resistant steel that cost is low is arranged again, so that satisfy the needs of usefulness materials such as Diesel Engine's Air Valve.

At above-mentioned purpose, the present invention adopts iron-based on chemical ingredients, so that reduce cost significantly, add proper C r, Ni, Mn, Al, Ti, Nb, Zr, Ce, Co, Cu element on the other hand in the steel, realize multiple strengthening, assurance has higher high temperature strength and hardness, excellent comprehensive performances such as good plasticity and toughness.Its concrete chemical ingredients (weight %) is as follows:

C 0.02～0.2%, and Si 0.1～1.5%, and Mn 0.4～1.5%, and Cr 17～23%, and Ni 20～28%, Al 0.7～2.0%, and Ti 1.80～3.2%, and Nb 0.7～2.0%, and Zr 0.01～0.2%, Ce 0.003～0.1%, and Co 0.1～3.0%, and Cu 0.05～0.5%, and surplus is Fe.

Adding an amount of Ti and the purpose of Al among the present invention, is the Ni for Ti, Al and Ni generation disperse distribution ₃(Al, Ti) phase, i.e. γ ' phase, γ ' is typical ageing strengthening phase mutually, because the effect of γ ', thereby guarantee that this steel at high temperature has high intensity and hardness.

Niobium and zirconium are the strong carbide forming elements, it can improve the hot strength of steel effectively, niobium and zirconium once at high temperature very stable with proeutectoid carbide, therefore, guarantee certain high temperature intensity, hot hardness and wear resistance, crystal grain thinning is gone back in the formation of the carbide of niobium and zirconium simultaneously, improves plasticity, also improves hot workability.

Chromium is the important element of steel, a certain amount of chromium is to guarantee that steel at high temperature has good anti-oxidant and anti-exhaust gas corrosion performance, chromium also forms the intensity that carbide improves steel, and excessive chromium worsens the thermoplasticity of steel, and therefore the tissue instability contains 17～23%Cr and be advisable.

The adding of nickel, cobalt, manganese at first is to make the steel austenitizing, and simultaneously, the adding of nickel and titanium, aluminium form γ ' strengthening phase.Certain nickel cobalt contents guarantees the high temperature thermoplasticity of steel, improves the forgeability of steel.Improve the hot strength of steel simultaneously owing to solution strengthening.

Cerium is a rare earth element, and it improves Ingot Surface Quality, and refinement ingot crystal tissue reduces dendrite, thereby improves the hot workability of steel ingot; Cerium has been eliminated the enrichment of harmful elements such as sulphur phosphorus at crystal boundary in crystal grain thinning, eliminate sulphur or low melting components such as lead, arsenic; Cerium also enters carbide, makes carbide spheroidization and size decreases, is evenly distributed; Cerium also makes oxygen level reduction in the steel, thereby improves the thermoplasticity of steel.In addition, behind the adding cerium, at high temperature using, cerium improves the structure of oxide on surface, makes the form of oxidation spherical in shape, helps anti-oxidant, anti-exhaust gas corrosion.

The present invention adopts vacuum induction furnace smelting, be cast into ingot after, forge or rolling hot-work, be cold worked into finished product at last.

Compared with prior art, the present invention has following advantage:

1, ferrous alloy, cost is low.

2, have enough hot strengths and hot hardness, make its air valve of making that high hot strength be arranged, therefore, can reduce the air valve size, weight reduction has not only reduced cost, also can alleviate the surging force of air valve to valve seat, alleviates wearing and tearing, increases the service life.

3, production technique is simple, and the yield rate height.

4, the locomotive naval vessel uses the high-speed high-power diesel valve overwhelming majority to adopt the structures of built-up welding Stellite6 at present, with the waste product that can eliminate behind the present invention in the weld deposit process, overcome the accident that overlay cladding exists defective in use to lose efficacy, the transportation safety that improves air valve life-span and locomotive, ships guarantees.

Embodiment

Chemical ingredients scope designed according to this invention is prepared burden, and has smelted 8 stove steel on vacuum induction furnace.In order to contrast, under with the equipment similarity condition, also smelt correlated Ni-based Inconel751 of closing of two stoves and NiCr ₂₀TiAl, its concrete chemical ingredients is as shown in table 1.Embodiment and Comparative Examples are carried out hammer cogging and timeliness thermal treatment subsequently after smelting and being cast into ingot; Take a sample after the ageing treatment, carry out the test of room temperature and mechanical behavior under high temperature respectively, its result lists table 2 and table 3 respectively in.

Find out by table 2 and table 3, the actual performance level that reaches the Comparative Examples nickel-base alloy of the room temperature of ferrous alloy of the present invention and mechanical behavior under high temperature, and reduced cost widely.

Table 1 embodiment chemical ingredients (weight %)

Heat (batch) number		????C	????Si	????Mn	????Cr	????Ni	????Fe	????Co	????Al	????Ti	????Nb	????Zr	????Ce	????Cu
Heat (batch) number		????C	????Si	????Mn	????Cr	????Ni	????Fe	????Co	????Al	????Ti	????Nb	????Zr	????Ce	????Cu	The present invention	????1	??0.024	??0.21	??0.58	??21.48	??21.63	Surplus	??0.58	??1.47	??2.71	??1.01	??0.028	??0.005	??0.10
????2	??0.061	??0.20	??0.56	??21.63	??24.90	Surplus	??0.99	??1.73	??2.94	??0.74	??0.027	??0.005	??0.09			????1	??0.024	??0.21	??0.58	??21.48	??21.63	Surplus	??0.58	??1.47	??2.71	??1.01	??0.028	??0.005	??0.10
????2	??0.061	??0.20	??0.56	??21.63	??24.90	Surplus	??0.99	??1.73	??2.94	??0.74	??0.027	??0.005	??0.09	????3		??0.075	??0.23	??0.58	??21.37	??24.52	Surplus	??1.02	??1.57	??2.62	??1.47	??0.023	??0.007	??0.08
????4	??0.051	??0.20	??0.58	??21.02	??22.26	Surplus	??2.05	??0.71	??2.10	??0.83	??0.014	??0.005	??0.08	????3		??0.075	??0.23	??0.58	??21.37	??24.52	Surplus	??1.02	??1.57	??2.62	??1.47	??0.023	??0.007	??0.08
????4	??0.051	??0.20	??0.58	??21.02	??22.26	Surplus	??2.05	??0.71	??2.10	??0.83	??0.014	??0.005	??0.08	????5		??0.084	??0.14	??0.56	??21.26	??21.52	Surplus	??1.53	??1.13	??2.45	??0.86	??0.025	??0.008	??0.09
????6	??0.087	??0.21	??0.57	??19.86	??27.54	Surplus	??1.09	??0.73	??1.97	??0.89	??0.027	??0.005	??0.08	????5		??0.084	??0.14	??0.56	??21.26	??21.52	Surplus	??1.53	??1.13	??2.45	??0.86	??0.025	??0.008	??0.09
????6	??0.087	??0.21	??0.57	??19.86	??27.54	Surplus	??1.09	??0.73	??1.97	??0.89	??0.027	??0.005	??0.08	????7		??0.066	??0.21	??0.58	??17.47	??24.01	Surplus	??1.07	??1.12	??2.23	??0.96	??0.028	??0.006	??0.10
????8	??0.061	??0.21	??0.56	??19.71	??28.00	Surplus	??2.35	??1.17	??2.29	??0.89	??0.027	??0.008	??0.09	????7		??0.066	??0.21	??0.58	??17.47	??24.01	Surplus	??1.07	??1.12	??2.23	??0.96	??0.028	??0.006	??0.10
????8	??0.061	??0.21	??0.56	??19.71	??28.00	Surplus	??2.35	??1.17	??2.29	??0.89	??0.027	??0.008	??0.09	??Incone1751		??0.055	??0.14	??0.77	??15.32	Surplus	??6.99	????/	??1.10	??2.26	??0.93			??＜0.05
??NiCr20TiA		??0.092	??0.54	??0.80	??19.68	Surplus	??0.2	??1.07	??1.52	??2.46	????/			??Incone1751		??0.055	??0.14	??0.77	??15.32	Surplus	??6.99	????/	??1.10	??2.26	??0.93			??＜0.05	????/

Table 2 embodiment room temperature (22 ℃) mechanical property

Heat (batch) number		????σ ₆????MPa	???σ _0.2????MPa	????δ ₅?????％	?????ψ ?????％	????HV1
Heat (batch) number		????σ ₆????MPa	???σ _0.2????MPa	????δ ₅?????％	?????ψ ?????％	????HV1	The present invention	????1	???1358	????1200	????8.0	????19.5	????355
????2	???1280	????1060	???13.0	????36.0	????342			????1	???1358	????1200	????8.0	????19.5	????355
????2	???1280	????1060	???13.0	????36.0	????342	????3		???1555	????1310	????8.0	????23.0	????382
????4	???1080	????817.5	???21.5	????51.3	????283	????3		???1555	????1310	????8.0	????23.0	????382
????4	???1080	????817.5	???21.5	????51.3	????283	????5		???1325	????980	???18.0	????30.0	????Rc37
????6	???1190	????818	???23.0	????41.0	????283	????5		???1325	????980	???18.0	????30.0	????Rc37
????6	???1190	????818	???23.0	????41.0	????283	????7		???1230	????930	???18.5	????35.0	????Rc36
????8	???1220	????925	???19.0	????33.0	????Rc37	????7		???1230	????930	???18.5	????35.0	????Rc36
????8	???1220	????925	???19.0	????33.0	????Rc37	??Incone1751		???1265	????955	???18.7	????31.3	????Rc37
??NiCr20TiAl		???1120	????825	???20.5	????37.2	??Incone1751		???1265	????955	???18.7	????31.3	????Rc37	????Rc32

Table 3 embodiment mechanical behavior under high temperature

Heat (batch) number		Test temperature ℃	????σ ₅????MPa	?δ _0.2??％	??δ ₅??％	????ψ	??HV1
Heat (batch) number		Test temperature ℃	????σ ₅????MPa	?δ _0.2??％	??δ ₅??％	????ψ	??HV1	The present invention	????1	????700	????878	??735	??30	????57	??260
????2	????700	????903	??772	??19	????30	??274			????1	????700	????878	??735	??30	????57	??260
????2	????700	????903	??772	??19	????30	??274	????3		????700	????903	??735	??20	????36	??269
????4	????700	????790	??745	??23.5	????40	??214	????3		????700	????903	??735	??20	????36	??269
????4	????700	????790	??745	??23.5	????40	??214	????5		????700	????690	??548	???9.5	????17.5	??224
????6	????700	????773	??630	??23.5	????37.3	??234	????5		????700	????690	??548	???9.5	????17.5	??224
????6	????700	????773	??630	??23.5	????37.3	??234	????7		????700	????710	??610	??18.0	????25.0	??229
????8	????700	????715	??620	??19.0	????29.0	??229	????7		????700	????710	??610	??18.0	????25.0	??229
????8	????700	????715	??620	??19.0	????29.0	??229	??Incone1751		????700	????785	??645	???7.6	????13.9	??234
??NiCr20TiAl		????700	????881	??715	???7.6	????13.5	??Incone1751		????700	????785	??645	???7.6	????13.9	??234	??260

Claims

1, a kind of high strength heat resistant steel, it is characterized in that chemical ingredients (weight %)/be: C 0.02～0.2%, and Si 0.1～1.5%, Mn 0.4～1.5%, and Cr 17～23%, and Ni 20～28%, Al 0.7～2.0%, Ti 1.80～3.2%, and Nb 0.7～2.0%, and Zr 0.01～0.2%, Ce 0.003～0.1%, Co 0.1～3.0%, and Cu 0.05～0.5%, and surplus is Fe.