CN101525726A - Heat-resisting steel material used as vane or bolt of supercritical steam turbine and preparation method thereof - Google Patents

Abstract

The invention discloses a heat-resisting steel material used as a vane or a bolt of a supercritical steam turbine. The chemical composition of the material (in percentage by weight) is: 0.12 to 0.16 percent of C, 0.30 to 0.70 percent of Mn, 0.35 to 0.65 percent of Ni, 10.0 to 11.0 percent of Cr, 0.30 to 0.5 percent of Mo, 1.5 to 1.9 percent of W, 0.14 to 0.20 percent of V, 0.05 to 0.11 percent of Nb, 0.04 to 0.08 percent of N, and the balance of Fe and impurities. The chemical property of the material is that: tensile strength sigma b is more than or equal to 930MPa; yield strength sigma 0.2 is more than or equal to 765MPa; tensile stretch delta is more than or equal to 14 percent; percentage of area reduction psi is more than or equal to 32 percent; ballistic work AKv is more than or equal to 20J; and hardness HB is between 277 and 331.

Description

Be used as heat-resisting steel material of supercritical pressure turbine blade or bolt and preparation method thereof

Technical field

The present invention relates to turbine materials, relate in particular to a kind of heat-resisting steel material that is used as supercritical pressure turbine blade or bolt and preparation method thereof.

Background technology

Along with the development of steam turbine manufacturing technology, single-machine capacity is increasing, and steam turbine develops to supercritical unit, and its working temperature is brought up to 550 ℃, and the mechanical property of existing turbine blade and bolt material can not satisfy the service requirements of this operating mode.

Summary of the invention

The problem to be solved in the present invention is that a kind of heat-resisting steel material that is used as supercritical pressure turbine blade and bolt will be provided, and the mechanical property of this material satisfies above-mentioned requirements.

Technical scheme of the present invention is:

A kind of high temperature steel that is used as turbine blade and bolt, its chemical constitution (weight percent) is:

C 0.12～0.16；Mn 0.30～0.70；Ni 0.35～0.65；

Cr 10.0～11.0；Mo 0.30～0.5； W 1.5～1.9；

V 0.14～0.20；Nb 0.05～0.11；N 0.04～0.08；

Surplus is Fe and unavoidable impurities.

Described impurity (weight percent) is:

Si≤0.10；S≤0.015；P≤0.015；Al≤0.02；Cu≤0.10。

The smelting process of above-mentioned high temperature steel comprises step:

(1) gets the refining just in non-vacuum induction furnace of required element, 1530～1600 ℃ of smelting temperatures; Regulate the content of each element in fusion process, its weight ratio is adhered to specification, the content of control impurity element is low as far as possible, and solution casting becomes consumable electrode;

(2) with consumable electrode remelting refining in electroslag furnace, further reduce the content of impurity element, it is adhered to specification, make ESR ingot.

A kind of rod iron that is used as turbine blade or bolt, this rod iron is made with above-mentioned high temperature steel.

The manufacture method of above-mentioned rod iron comprises step:

1). with the ESR ingot heats forged or be rolled into rod iron;

2). the thermal treatment of annealing after rod iron is forged, step and processing parameter are as follows:

Rod iron is heated to 760 ℃, is incubated after 4 hours, in annealing furnace, be cooled to 680 ℃, and come out of the stove air cooling after being incubated 12～15 hours;

3). the rod iron surface treatment, the finished product rod iron is carried out surface grinding or car optical processing, eliminate surface imperfection and rod iron size, shape, surface quality are met design requirement;

4). finished product rod iron mechanical properties test, on the finished product rod iron, take a sample, carry out tensile test at room temperature;

--sample heat treatment step and processing parameter are as follows:

Quench: 1 hour Heating temperature 〉=1100 ℃ time; The type of cooling: oil cooling

Tempering: 2 hours Heating temperature 〉=650 ℃ time; The type of cooling: air cooling

--the tensile test at room temperature technical requirements is as follows:

Tensile strength sigma _b〉=930MPa

Yield strength σ _0.2〉=765MPa

Elongation δ 〉=14%

Relative reduction in area ψ 〉=32%

Ballistic work AKv 〉=20J

Hardness HB 277～331.

Technique effect of the present invention:

Adopt the turbine blade and the bolt material of the preparation of above-mentioned materials and corresponding process method, through tensile test at room temperature, the result shows that its mechanical property reaches design requirements fully, and test-results is as follows:

σ b	σ 0.02	δ	ψ	AKv	HB
						N/mm 2	N/mm 2	％	％	J
1010	860	19	59	40	302
						1010	865	17.5	59	39	307
1020	880	19	57.5	40	304
						1020	855	20	59	40	309

Turbine blade and bolt with this material is made can satisfy 550 ℃ of service requirementss under the steam parameter operating mode.

Embodiment

Enforcement the present invention includes following steps:

One, smelts

(1) gets the refining just in non-vacuum induction furnace of required element, 1530～1600 ℃ of smelting temperatures; In fusion process, regulate the content of each element, make its weight percent as follows:

	C	Mn	Ni	Cr	W	V	Nb	N	Mo	Fe
											Embodiment 1	0.13	0.58	0.55	10.56	1.6	0.165	0.09	0.054	0.36	Surplus
Embodiment 2	0.13	0.65	0.55	10.40	1.61	0.19	0.10	0.048	0.39	Surplus
											Embodiment 3	0.13	0.64	0.54	10.55	1.64	0.19	0.10	0.046	0.35	Surplus
Embodiment 4	0.13	0.54	0.53	10.31	1.61	0.18	0.09	0.07	0.31	Surplus
											Embodiment 5	0.13	0.60	0.55	10.44	1.62	0.18	0.10	0.053	0.31	Surplus

And the content of control impurity element is low as far as possible, and solution casting becomes consumable electrode;

(2) with consumable electrode remelting refining in electroslag furnace, further reduce the content of impurity element, make it meet following requirement:

Si≤0.10 (weight percent); S≤0.015 (weight percent);

P≤0.015 (weight percent); Al≤0.02 (weight percent);

Cu≤0.10 (weight percent).

Make ESR ingot after the component concentration analysis is qualified.

Two, ESR ingot is made rod iron, comprises step:

1). with the ESR ingot heats forged or be rolled into rod iron;

2). the thermal treatment of annealing after rod iron is forged, step and processing parameter are as follows:

Rod iron is heated to 760 ℃, is incubated after 4 hours, in annealing furnace, be cooled to 680 ℃, and come out of the stove air cooling after being incubated 12～15 hours;

3). the rod iron surface treatment, the finished product rod iron is carried out surface grinding or car optical processing, eliminate surface imperfection and rod iron size, shape, surface quality are met design requirement;

4). finished product rod iron mechanical properties test, on the finished product rod iron, take a sample, carry out tensile test at room temperature;

--sample heat treatment step and processing parameter are as follows:

Quench: Heating temperature 〉=1100 ℃, 1 hour time; The type of cooling: oil cooling

Tempering: Heating temperature 〉=650 ℃, 2 hours time; The type of cooling: air cooling

--the tensile test at room temperature technical requirements is as follows:

Tensile strength sigma _b〉=930MPa

Yield strength σ _0.2〉=765MPa

Elongation δ 〉=14%

Relative reduction in area ψ 〉=32%

Ballistic work AKv 〉=20J

Hardness HB 277～331

Stand the test is product.

Claims (5)

1. a high temperature steel that is used as turbine blade or bolt is characterized in that, the chemical constitution of described high temperature steel is:

C 0.12～0.16 (weight percent); Mn 0.30～0.70 (weight percent);

Ni 0.35～0.65 (weight percent); Cr 10.0～11.0 (weight percent);

Mo 0.30～0.5 (weight percent); W 1.5～1.9 (weight percent;

V 0.14～0.20 (weight percent); Nb 0.05～0.11 (weight percent);

N 0.04～0.08 (weight percent);

Surplus is Fe and impurity.

2. the high temperature steel that is used as turbine blade or bolt according to claim 1 is characterized in that, described impurity is:

Si≤0.10 (weight percent); S≤0.015 (weight percent);

P≤0.015 (weight percent); Al≤0.02 (weight percent);

Cu≤0.10 (weight percent).

3. the smelting process of the described high temperature steel of claim 1 comprises step:

(1) gets the refining just in non-vacuum induction furnace of required element, 1530～1600 ℃ of smelting temperatures; Regulate the content of each element in fusion process, its weight ratio is adhered to specification, the content of control impurity element is low as far as possible, and solution casting becomes consumable electrode;

(2) with consumable electrode remelting refining in electroslag furnace, further reduce the content of impurity element, it is adhered to specification, make ESR ingot.

4. a rod iron that is used as turbine blade or bolt is characterized in that, this rod iron is made with the described high temperature steel of claim 1.

5. the manufacture method of the described rod iron of claim 4 comprises step:

1). with the ESR ingot heats forged or be rolled into rod iron;

2). the thermal treatment of annealing after rod iron is forged, step and processing parameter are as follows:

With rod iron be heated to 760 ℃ of insulations in annealing furnace, be cooled to after 4 hours 680 ℃ and be incubated 12～20 hours after the air cooling of coming out of the stove;

3). the rod iron surface treatment, the finished product rod iron is carried out surface grinding or car optical processing, eliminate surface imperfection and rod iron size, shape, surface quality are met design requirement, make the finished product rod iron;

4). inspection by sampling mechanical property on the finished product rod iron, carry out tensile test at room temperature;

--sample heat treatment step and processing parameter are as follows:

Quench: 1 hour Heating temperature 〉=1100 ℃ time; The type of cooling: oil cooling

Tempering: 2 hours Heating temperature 〉=650 ℃ time; The type of cooling: air cooling

--the technical requirements of sample tensile test at room temperature is as follows:

Tensile strength sigma _b〉=930MPa

Yield strength σ _0.2〉=765MPa

Elongation δ 〉=14%

Relative reduction in area ψ 〉=32%

Ballistic work AKv 〉=20J

Hardness HB277～331.