WO2018016878A1 - Heat-resistant cast steel for turbocharger turbine housing, requiring less tungsten, and turbocharger turbine housing using same - Google Patents

Abstract

The present invention relates to heat-resistant cast steel for a turbocharger turbine housing and to a turbocharger turbine housing using same, the heat-resistant cast steel for a turbocharger turbine housing comprising 0.40-0.50 wt% of carbon (C), 1.0-2.0 wt% of silicon (Si), 1.0-2.0 wt% of manganese (Mn), 9.0-12.0 wt% of nickel (Ni), 21-24 wt% of chromium (Cr), 1.0-2.5 wt% of niobium (Nb), 0.5-2.2 wt% of tungsten (W), 0.045 wt% or less of phosphorus (P), and 0.05-0.18 wt% of sulfur (S), with the remainder being iron (Fe), the heat-resistant cast steel allowing for the production of a turbocharger turbine housing requiring the addition of high-cost tungsten as little as possible and yet having improved thermal fatigue life and mechanical durability at high temperatures.

Description

Heat-resistant cast steel for tungsten-reduced turbocharged turbine housings and turbocharged turbine housings using the same

The present invention relates to a heat resistant cast steel for tungsten reduction type turbocharger turbine housing having excellent physical properties at high temperature, and a turbocharger turbine housing manufactured using the same.

The turbocharger improves the output of the engine by compressing and supplying more air into the cylinder of the engine. The turbocharger rotates a turbine wheel in a turbine housing using exhaust gas emitted from the engine. It is made of a structure that is supplied to the engine by rotating a compressor wheel (compressor wheel) in the compressor housing (compressor housing) for transmitting the rotational force generated during the rotation of the turbine wheel to compress the air of the atmosphere.

Turbine housing surrounding the turbine wheel is in constant contact with the exhaust gas of 800 ℃ ~ 900 ℃ discharged from the engine is subjected to a very high thermal shock depending on the engine output turbine housing requires a high thermal durability.

At present, the material used for the turbine housing of the vehicle is made of high heat resistant austenitic stainless steel, but in the case of the high heat resistant austenitic stainless steel, at least 2.5% by weight of expensive tungsten (W) and nickel ( Ni) is used in a large amount of about 19 to 22% by weight and additionally contains molybdenum (Mo), there is a problem that the cost is expensive and the commercial viability is greatly reduced.

The matters described as the background art are only for the purpose of improving the understanding of the background of the present invention, and should not be taken as acknowledging that they correspond to the related art already known to those skilled in the art.

The present invention has been proposed to solve this problem, and an object thereof is to provide a heat-resistant cast steel and a turbocharger turbine housing manufactured using the same, which has high durability at a high temperature while adding a high cost of tungsten to a minimum.

An object of the present invention is to provide a heat-resistant cast steel for tungsten reduction turbocharger turbine housing, the heat-resistant cast steel of the present invention is 0.40 ~ 0.50% by weight of carbon (C), 1.0 ~ 2.0% by weight of silicon (Si), manganese (Mn) ) 1.0 to 2.0 wt%, nickel (Ni) 9.0 to 12.0 wt%, chromium (Cr) 21 to 24 wt%, niobium (Nb) 1.0 to 2.5 wt%, tungsten (W) 0.5 to 2.2 wt%, phosphorus (P ) 0.045 wt% or less, sulfur (S) 0.05 to 0.18 wt% and the balance iron (Fe).

According to a preferred embodiment of the present invention, the heat-resistant cast steel of the present invention is 0.42 to 0.48 wt% carbon, 1.25 to 1.75 wt% silicon, 1.2 to 1.8 wt% manganese, 9.5 to 11.5 wt% nickel, chromium 21.5 to 23.5 wt% , Niobium 1.0 to 2.2 wt%, tungsten 0.7 to 2.1 wt%, phosphorus 0.040 wt% or less, sulfur 0.10 to 0.18 wt% and the balance iron.

According to a preferred embodiment of the present invention, the heat-resistant cast steel of the present invention is one selected from molybdenum (Mo) and aluminum (Al) in addition to the carbon, silicon, manganese, nickel, chromium, niobium, tungsten, phosphorus, sulfur and iron. It may further include the above.

According to a preferred embodiment of the present invention, the heat-resistant cast steel of the present invention may include niobium in an amount of 1.2 to 2.2% by weight.

According to a preferred embodiment of the present invention, the heat-resistant cast steel of the present invention may comprise 0.8 to 2.2% by weight of tungsten.

According to a preferred embodiment of the present invention, the heat-resistant cast steel of the present invention may have a tensile strength of 180 ~ 210 Mpa at 900 ℃, measured according to the ASTM E8 rod test standard.

According to a preferred embodiment of the present invention, the heat-resistant cast steel of the present invention may have a yield strength of 150 ~ 180 Mpa at 900 ℃, measured according to the ASTM E8 rod test standard.

According to a preferred embodiment of the present invention, the heat-resistant cast steel of the present invention may have an elongation of 25.0 to 32.0% at 900 ° C., measured according to ASTM E8 rod test standard.

According to a preferred embodiment of the present invention, the heat-resistant cast steel of the present invention is (0.70 ~ 1.00) × 10 ³ (Number of when measured by Thermo-Mechanical Fatigue testing (TMF) based on ASTM E 2368 test standard) cycles to failure).

Another object of the present invention is to provide a turbocharger turbine housing manufactured using the various types of heat-resistant cast steel described above.

According to the heat-resistant cast steel of the present invention as described above and the turbocharged housing manufactured using the same, the turbocharger with improved mechanical durability and heat fatigue life at the required high temperature (up to 950 ° C) while adding a high cost tungsten to a minimum The housing can be manufactured.

1 is a cross-sectional view of the specimen prepared in Example 1.

Figure 2 is a graph showing the results of room temperature tensile test according to Examples 1 to 2 and Comparative Examples 1 to 2 of the present invention.

Figure 3 is a graph showing the high temperature tensile test results according to Examples 1 and 2 and Comparative Examples 1 and 2 of the present invention.

4 is a Schaeffler Diagram according to Examples 1 to 2 and Comparative Examples 1 to 2 of the present invention.

FIG. 5 is a graph illustrating a strain rate of each alloy as a heat fatigue life evaluation result according to Examples 1 to 2 and Comparative Example 1 of the present invention.

6 is a graph showing thermal fatigue life values as a result of thermal fatigue life evaluation according to Examples 1 to 2 and Comparative Example 1 of the present invention.

Hereinafter, the present invention will be described in more detail.

Heat-resistant cast steel of the present invention minimizes the content of tungsten, while having a physical property that can replace the existing high heat-resistant austenitic stainless steel, which is a material used in the turbine housing of the current vehicle, and excellent heat-resistant cast steel (or stainless steel) will be.

The heat-resistant cast steel of the present invention is an austenitic heat-resistant cast steel, carbon (C), silicon (Si), manganese (Mn), nickel (Ni), chromium (Cr), niobium (Nb), tungsten ( W), phosphorus (P), sulfur (S) and iron (Fe), and the heat-resistant cast steel of the present invention is excellent in tensile strength and elongation at high temperatures of 800 ℃ ~ 950 ℃ Ideal for turbocharged turbine housings operating in high temperature environments.

Among the heat-resistant cast steel components of the present invention, the carbon (C) is known to be a strong austenite stabilizing element, and is also strengthened in a matrix structure and plays an important role in maintaining the strength of the heat-resistant cast steel at high temperatures. In addition, by forming a carbide (Carbide) by combining with a carbide former (Carbide former), such as chromium (Cr), niobium (Nb), it improves the castability of the liquid phase and the high temperature strength. Heat-resistant cast steel of the present invention may include carbon of 0.40 to 0.50% by weight, preferably 0.42 to 0.48% by weight, more preferably 0.43 to 0.47% by weight of the total weight of the heat-resistant cast steel. In this case, if the carbon content is less than 0.40% by weight of the total weight of the heat-resistant cast steel, there may be a problem in that the carbon does not effectively exhibit the function of contributing to high temperature strength through the formation of strong carbides and strengthening solid solution in the austenitic matrix structure. If the content exceeds 0.50% by weight, strong carbides may be excessively formed and become brittle, and such carbides may be used as a starting point and propagation site of fracture under a thermodynamic fatigue environment, thereby reducing the high temperature properties of the cast steel.

Silicon (Si) has the effect of improving the high temperature oxidation resistance, and serves as a deoxidizer in the melt (melt) of the alloy. Silicon improves oxidation resistance by playing a role in preventing oxidation by chromium (Cr). Silica particles formed by silicon are precipitated under the film formed on the surface of the alloy by chromium to assist in the formation of the passivation film, and to suppress the unnecessary escape of chromium ions. In particular, this effect of silicon is further enhanced at high temperatures. Heat-resistant cast steel of the present invention may include silicon in the total weight of the heat-resistant cast steel 1.0 to 2.0% by weight, preferably 1.25 to 1.75% by weight, if the silicon content is less than 1.0% by weight of the total weight of the heat-resistant cast steel chromium ion The anti-oxidation effect can be greatly reduced, and if the silicon content exceeds 2.0% by weight, the high temperature creep resistance is lowered, and as a ferrite stabilizing element, the austenite matrix may be unstable. It is good to contain in the range.

Manganese (Mn) in the total weight of the heat-resistant cast steel acts as an austenite stabilizing element, and acts as a deoxidizer in the melt (melt) with silicon (Si). Heat-resistant cast steel of the present invention includes a manganese content of 1.0 to 2.0% by weight, preferably 1.2 to 1.8% by weight, more preferably 1.35 to 1.7% by weight of the total weight of the heat-resistant cast steel, wherein the content of manganese is heat-resistant cast steel If less than 1.0% by weight of the total weight may cause a problem that the effect according to the manganese content is insignificant, and if it exceeds 2.0% by weight may lower the oxidation resistance and creep strength rather preferably contained within the above range .

Nickel (Ni) is a strong austenite stabilizing element and is generally added in an amount of at least 9% by weight to austenitic stainless steel (STS). When nickel is added to stainless steel, the alloy has excellent performance in terms of corrosion resistance and high temperature stabilization along with increased toughness and ductility. In contrast, the heat-resistant cast steel of the present invention includes nickel in the total weight of the heat-resistant cast steel is 9.0 to 12.0% by weight, preferably 9.5 to 11.5% by weight, more preferably 10.0 to 11.0% by weight, wherein the nickel content is heat-resistant If less than 9.0% by weight of the total weight of the cast steel may not secure the proper tensile strength and yield strength at high temperatures, when exceeding 12.0% by weight is excellent mechanical properties at high temperatures, but there is a problem that the thermal fatigue life is poor There is a number.

Chromium (Cr) is one of the key elements for the oxidation resistance, corrosion resistance of the heat-resistant cast steel, Cr on the surface of the heat-resistant cast steel ₂ O ₃ It forms a stable passivation film in the form and serves as a ferrite stabilizing element to improve oxidation resistance and corrosion resistance at high temperatures. Heat-resistant cast steel of the present invention may include 21 to 24% by weight, preferably 21.5 to 23.5% by weight, more preferably 21.5 to 23.0% by weight of the total weight of the heat-resistant cast steel, wherein the total weight of the heat-resistant cast steel If the heavy chromium content is less than 21% by weight, it may not secure high temperature corrosion resistance and oxidation resistance, and if it exceeds 24% by weight, the ferrite phase may be formed and a large amount of carbide may be formed unnecessarily, so it is used within the above range. Good to do.

Niobium (Nb) combines with carbon (C) to form carbides that do not decompose at high temperatures, which is effective in improving high temperature strength and high temperature creep sexixtance. In addition, chromium (Cr) and carbon are combined to inhibit the formation of chromium-carbide (Cr-carbide), thereby improving oxidation resistance. Niobium carbide is formed in the eutectic form to improve the castability, it is effective in the production of complex castings, such as automotive exhaust systems. Heat-resistant cast steel of the present invention may include niobium content of 1.0 to 2.5% by weight, preferably 1.0 to 2.2% by weight, preferably 1.2 to 1.8% by weight of the total weight of the heat-resistant cast steel, niobium content of the total weight of heat-resistant cast steel If the amount is less than 1.0 wt%, there may be a problem that the mechanical properties and thermal fatigue life stability at high temperatures are inferior, and when it is used more than 2.5 wt%, a large amount of niobium carbide is formed at the cell boundary, and thus the heat resistant cast steel may be easily broken. It can be brittle and can rather reduce the strength and ductility.

In the case of heat-resistant cast steel for turbocharged turbine housings, the turbocharger is driven under environmental conditions in which thermal fatigue and vibration occur at high temperatures. Therefore, excellent thermo-mechanical fatigue life is required and properties such as proper toughness strength are required. . By the way, tungsten (W) is an element having a strengthening effect of tensile strength and yield strength at high temperature by being dissolved in a matrix of heat-resistant cast steel. As the tungsten content increases, the tensile property tends to be improved, but the tungsten content increases. There is a problem that the improvement in tensile properties and thermo-mechanical fatigue life are not in proportion to each other. Therefore, it is advantageous to control the tungsten content in an appropriate amount, the heat-resistant cast steel of the present invention is 0.5 to 2.2% by weight, preferably 0.7 to 2.1% by weight, more preferably 0.95 to 2.05% by weight of the total weight of the heat-resistant cast steel It may include. At this time, when the tungsten content is less than 0.5% by weight, it may not be possible to secure an appropriate tensile strength and yield strength at high temperature. And, if the tungsten exceeds 2.2% by weight, it can be combined with carbon to form carbides in the form of M2C, M7C3, and the heat resistant cast steel of the present invention is required as a turbocharger turbine housing even if it contains only about 2.2% by weight of tungsten. It is uneconomical to use tungsten, which is an expensive element, any longer, because it can satisfy the physical properties.

Heat-resistant cast steel of the present invention may contain phosphorus (P) 0.045% by weight or less, preferably 0.04% by weight or less, more preferably 0.01 to 0.04% by weight, it is possible to completely remove the phosphorus component, Performing an ancillary process to remove this completely is undesirable from an economical point of view, and in the case of containing phosphorus at 0.045% by weight or less, it is possible to secure the physical properties to be obtained as a turbocharger turbine housing material. If it exceeds 0.045% by weight segregation in the heat-resistant cast steel may occur, it is preferable to include phosphorus in the above range.

Sulfur (S) of the heat-resistant cast steel of the present invention forms a sulfide (sulfide) such as MnS in the heat-resistant cast steel to improve the workability of the heat-resistant cast steel, the content of sulfur is 0.05 ~ 0.18 weight of the total weight of the heat-resistant cast steel %, Preferably from 0.10 to 0.18% by weight, more preferably from 0.12 to 0.17% by weight, wherein if the sulfur content is less than 0.05% by weight, it may not be possible to secure the workability of the heat-resistant cast steel, sulfur When the content is more than 0.18% by weight, it is preferable to include the sulfide in the above range because too much sulfide may occur and thus lower the overall physical properties of the heat resistant cast steel.

Heat-resistant cast steel of the present invention is carbon (C), silicon (Si), manganese (Mn), nickel (Ni), chromium (Cr), niobium (Nb), tungsten (W), phosphorus (P), sulfur (S) And in addition to iron (Fe) may include inevitable impurities during the manufacturing process, these impurities may be present in a very small amount of less than 1ppm, it is preferable that there are no impurities other than the above components.

Heat-resistant cast steel of the present invention having the composition described above may have a tensile strength of 180 ~ 210 Mpa, preferably a tensile strength of 182 ~ 205 Mpa at 900 ℃ measured according to the ASTM E8 rod test standard.

In addition, the heat-resistant cast steel of the present invention may have a yield strength of 150 ~ 180 Mpa, preferably 152 ~ 175 Mpa at 900 ℃, measured according to the ASTM E8 rod test standard.

In addition, the heat-resistant cast steel of the present invention may have an elongation of 25.0 to 32%, preferably 25.0 to 31.0% at 900 ° C., measured according to ASTM E8 rod test standard.

Since the turbocharger housing is in direct contact with the exhaust gas of the vehicle, the turbocharger housing should be able to maintain physical properties under high temperature environmental conditions of 800 ° C. to 900 ° C. The heat-resistant cast steel of the present invention may be used under 900 ° C. to 950 ° C. It has excellent mechanical properties and is suitable for use as a turbocharger housing material.

In addition, the heat-resistant cast steel of the present invention is a thermal fatigue of (0.70 ~ 1.00) × 10 ³ N (Number of cycles to failure) when measuring thermal-mechanical fatigue testing (TMF) based on ASTM E 2368 test standard It is possible to have a lifetime value, preferably a thermal fatigue life value of (0.75 to 0.95) × 10 ³ N, and more preferably a thermal fatigue life value of (0.80 to 0.92) × 10 ³ N. The turbocharger housing which ensured stability can be provided.

Hereinafter, preferred examples and experimental examples are presented to help understand the present invention. However, the following examples and examples are merely to aid the understanding of the present invention, the present invention is not limited by the following examples and experimental examples.

EXAMPLE

Example  One

Requested by Castek Korea Co., Ltd., a rod-like specimen having a composition as shown in Table 2 was prepared. At this time, the specimen is a rod-shaped specimen in the form according to the rod test standard in ASTM E8, the specifications are shown in Table 1 below.

Length of reduced section (A)	Diameter (D)	Gage length (G)	Radius of filet (R)
1.25	0.250? 0.005	1.0? 0.005	3/16

Example  2 to Example  6 and Comparative example  1 to 6

Requested by a casting company such as Castec Korea Co., Ltd., the rod-shaped specimens of the same form as in Example 1 were prepared, and Examples 2 to 6 and Comparative Examples 1 to 6 were carried out, respectively. Is shown in Table 2 below.

division	C	Si	Mn	P	S	Ni	Cr	Nb	W	Mo	Al	Fe
Example 1	0.45	1.5	1.5	0.04	0.15	10	22	1.5	One	-	-	Total weight% of heat-resistant cast steel
Example 2	0.45	1.5	1.5	0.04	0.15	10	22	1.5	2	-	-
Example 3	0.45	1.5	1.5	0.04	0.15	10	22	1.5	1.5	-	-
Example 4	0.47	1.7	1.3	0.035	0.12	11	20	1.65	1.8	-	-
Example 5	0.45	1.5	1.5	0.04	0.15	10	22	1.5	2	One	-
Example 6	0.45	1.5	1.5	0.04	0.15	10	22	1.5	2	One	One
Comparative Example 1	0.45	1.5	1.5	0.04	0.15	10	22	1.5	3	-	-
Comparative Example 2	0.44	1.17	0.69	0.04	0.14	9.8	20.1	1.22	2.53	-	-
Comparative Example 3	0.45	1.5	1.5	0.04	0.20	10	22	1.5	2	-	-
Comparative Example 4	0.45	1.5	1.5	0.04	0.15	10	22	0.7	2	-	-
Comparative Example 5	0.45	1.5	1.5	0.04	0.15	10	22	2.7	2	-	-
Comparative Example 6	0.45	1.5	1.5	0.04	0.15	12.5	22	1.5	One	-	-

Experimental Example  1: Mechanical property measurement experiment

Yield strength, tensile strength and elongation were respectively measured at room temperature (about 25 ° C.) and high temperature (900 ° C.) according to ASTM E8, using the rod-shaped specimens prepared in Examples and Comparative Examples, respectively. Table 3 shows.

2 and 3 show Examples 1 and 2 and Comparative Examples 1 and 2 specimens as a result of tensile strength measurement at room temperature and high temperature. In addition, Schaeffler Diagram of Examples 1 to 2 and Comparative Examples 1 to 2 are shown in FIG. 4.

division	Room temperature			900 ℃
	Yield strength (MPa)	Tensile Strength (MPa)	Elongation (%)	Yield strength (MPa)	Tensile Strength (MPa)	Elongation (%)
Example 1	393	635	7.9	156	185	30.3
Example 2	405	639	7.7	172	203	25.3
Example 3	398	636	7.9	167	197	28.2
Example 4	389	645	7.7	176	205	26.0
Example 5	394	638	7.8	161	187	29.6
Example 6	392	641	8.0	154	192	30.6
Comparative Example 1	388	647	7.5	170	205	31.4
Comparative Example 2	365	548	7.0	149	177	30.0
Comparative Example 3	390	628	7.5	135	173	24.2
Comparative Example 4	392	640	7.9	151	188	30.5
Comparative Example 5	375	622	7.6	138	166	26.8
Comparative Example 6	409	642	7.6	183	218	25.5

Looking at the Table 3, in the case of the specimens of Examples 1 to 6, compared with Comparative Example 2 using a commercially available heat-resistant cast steel, the mechanical properties at a high temperature showed relatively better results.

In addition, when comparing Example 5, Example 6, and Example 1 with the addition of molybdenum and / or aluminum, the mechanical properties are improved due to the additional use of these components, but the composition of Examples 1 to 4 Since the mechanical properties for the turbocharger turbine housing are satisfied, it was confirmed that there is no need to add expensive molybdenum and / or aluminum.

And, in the case of Comparative Example 1 used in excess of 2.2% by weight and Comparative Example 6 used in excess of 12% by weight of nickel, compared with Example 1, the overall excellent mechanical properties. Referring to FIG. 4, which is a Schaeffler diagram according to an embodiment, Examples 1, 2, and 1 may increase the austenite stability compared to Comparative Example 2, thereby increasing the yield strength and tensile strength at high temperature. .

In addition, in the case of Comparative Example 3 in which sulfur was more than 0.18% by weight, compared with Example 1, overall mechanical properties at high temperatures were inferior.

In addition, in Comparative Example 4 having a niobium content of less than 1.0 wt%, there was no significant difference in mechanical properties when compared to Example 1, but in Comparative Example 5 having a niobium content of more than 2.5 wt%, it was compared with Example 1. Rather, tensile strength and elongation tended to decrease.

Experimental Example  2 : Heat fatigue  life span( Thermo Mechanical Fatigue testing, TMF ) Measure

Attached to the manifold of a turbocharger's automotive engine, it is a component that is mounted in a harsh environment that must withstand high exhaust gas temperatures directly and withstand engine vibration caused by combustion in the cylinder. A similar test to this condition is the Thermo mechanical fatigue TEST (TMF) test. The TMF test, which is similar to the repeated thermal shock test, one of the turbocharger durability tests, is the best method for evaluating the thermal fatigue life of turbine housing materials. .

Thus, after preparing the Y-block (Y-block) of the same composition as the rod-shaped specimens of Examples 1 to 6, Comparative Examples 1 to 2, Comparative Example 4 and Comparative Example 6, each of them was used TMF measurement was performed according to the ASTM E 2368 method, and the results are shown in Table 4 below.

And as a measurement result about Examples 1-2 and Comparative Example 1, the strain measurement result is shown in FIG. In this case, the larger the slope, the larger the strain, the poor the fatigue life.

In addition, the thermal fatigue life value measurement results for Examples 1 and 2 and Comparative Example 1 are shown in FIG.

division	N, number of cycles to failure
Example 1	(0.81 to 0.83) x 10 3 N
Example 2	(0.80 to 0.82) x 10 3 N
Example 3	(0.82 to 0.84) x 10 3 N
Example 4	(0.78-0.80) × 10 3 N
Example 5	(0.79 ~ 0.81) × 10 3 N
Example 6	(0.80 to 0.82) x 10 3 N
Comparative Example 1	(0.48-0.50) × 10 3 N
Comparative Example 2	(0.59-0.61) x 10 3 N
Comparative Example 4	(0.67 ~ 0.69) × 10 3 N
Comparative Example 6	(0.54-0.56) x 10 3 N

Looking at the measurement results of Table 4, in Examples 1 to 6, the thermal fatigue life value was 0.78 × 10 ³ N or more showed a very good thermal fatigue life stability.

On the contrary, in the case of Comparative Example 1 in which the tungsten content exceeded 2.2 wt%, the mechanical properties at high temperature were excellent, but the thermal fatigue life leading value was (0.48 to 0.50) × 10 ³ N. Stability was greatly reduced.

In addition, Comparative Example 2, Comparative Example 4 and Comparative Example 6 also showed a result of having a low thermal fatigue life value, compared to excellent mechanical properties at high temperatures.

Although the heat-resistant cast steel of the present invention reduced the tungsten content compared to the existing heat-resistant cast steel through the above examples and experimental examples, not only increase the yield strength, tensile strength and elongation at high temperature by increasing austenite stability, but also high temperature As a result of the excellent thermal fatigue life stability in the system, it was found that it is suitable for application as a turbocharger turbine housing material operating under high temperature.

Claims (7)

1. 0.40 to 0.50 wt% of carbon (C), 1.0 to 2.0 wt% of silicon (Si), 1.0 to 2.0 wt% of manganese (Mn), 9.0 to 12.0 wt% of nickel (Ni), 21 to 24 wt% of chromium (Cr), Niobium (Nb) 1.0 to 2.5% by weight, tungsten (W) 0.5 to 2.2% by weight, phosphorus (P) 0.045% by weight or less, sulfur (S) 0.05 to 0.18% by weight and the balance iron (Fe) Heat-resistant cast steel for tungsten reduction type turbocharger turbine housing.
2. According to claim 1, 0.42 to 0.48% carbon, 1.25 to 1.75% silicon, 1.2 to 1.8% manganese, 9.5 to 11.5% nickel, chromium 21.5-23.5%, niobium 1.0 to 2.2%, tungsten 0.7 ~ 2.1% by weight, phosphorus 0.040% by weight, sulfur 0.10 ~ 0.18% by weight, and the remainder of iron, heat-resistant cast steel for a tungsten reduced turbocharger turbine housing.
3. The heat-resistant cast steel for tungsten reduction type turbocharger turbine housing according to claim 1, further comprising at least one selected from molybdenum (Mo) and aluminum (Al).
4. The heat-resistant cast steel for tungsten reduced turbocharger turbine housing according to claim 1, wherein the tensile strength is 180 to 210 Mpa at 900 ° C as measured according to the ASTM E8 rod test standard.
5. The heat-resistant cast steel for tungsten reduced turbocharger turbine housing according to claim 1, characterized in that the yield strength is 150 to 180 Mpa at 900 ° C, measured according to ASTM E8 rod test standard.
6. The method according to claim 1, which is measured according to ASTM E8 rod test standard and when measured by Thermo-Mechanical Fatigue testing (TMF) according to ASTM E 2368 test standard, (0.70 to 1.00) × 10 ³ (Number Heat-resistant cast steel for tungsten-reduced turbocharger turbine housings, characterized by a thermal fatigue life value of cycles to failure).
7. Turbocharger turbine housing comprising a heat-resistant cast steel for turbocharger turbine housing of claim 1.

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