High-strength high-tenacity cast-state QT700-10 and production method thereof

Abstract

The invention belongs to the field of casting technologies and new materials and particularly relates to a high-strength high-tenacity cast-state QT700-10 and a production method thereof. Compared with ductile iron produced in the prior art, the high-strength high-tenacity cast-state QT700-10 has high strength and a high elongation rate, heat treatment is not needed, heavy metal, such as, Ni and Mo are not added in production, the tensile strength Rm in the cast state is larger than or equal to 700 MPa, the elongation rate A is larger than or equal to 10%, compared with the standard brand QT 450-10, the lowest tensile strength is improved by 55% under the same elongation rate; and compared with the standard brand QT 700-2, the lowest elongation rate is improved by four times under the same tensile strength. The high-strength high-tenacity cast-state QT700-10 can meet requirements of automobile ductile iron castings with high requirements for safety and comprehensive mechanical properties.

Description

technical field

[0001] The invention belongs to the field of casting technology and new materials, and in particular relates to high-strength and high-toughness cast QT700-10 and a production method thereof. Background technique

[0002] Ductile iron, especially high-strength and high-toughness ductile iron, is more and more widely used in the fields of construction machinery and auto parts, and many steel castings are gradually replaced by high-strength and toughness ductile iron. For some automotive safety parts, such as axle housings, steering knuckles, planetary wheel housings, differential housings, hubs, flange shafts, etc., are the main load-bearing parts, requiring parts to have high strength and good extensibility. At present, the national standard GB / T1348-2009 stipulates 15 grades for ductile iron materials, among which QT450-10, QT600-3, QT700-2 and other grades are commonly used. The former has higher elongation but lower tensile strength, and the latter The la...

Examples

Embodiment 1

[0036] Adjust the temperature of the electric furnace to 1530 ° C ~ 1550 ° C, add recarburizers and scrap steel to adjust the mass percentage of the chemical composition in the molten iron during the smelting process of the electric furnace, and adjust the chemical composition of the molten iron in the furnace to: C3.82%, Si 1.10%, P≤0.04%, CE 4.2%, Cr≤0.05%, Mn 0.40%, Sn≤0.013%, Cu 0.45%, S≤0.02%, other trace elements≤0.1%, high temperature for 8-10 minutes, Remove the slag to obtain pure molten iron; the obtained molten iron is spheroidized and inoculated, and the Sn content is adjusted. The molten iron of the above components is spheroidized, the bottom of the bag is inoculated once, and the Sn content is adjusted in the bag. The weight of the molten iron in one treatment is 750Kg , the spheroidizing treatment adopts the cover bag method, that is, the dam-type spheroidizing bag, and the bag is repaired according to the technical requirements before use, and the spheroidizing...

Embodiment 2

[0038] The production method adopted is the same as that of Example 1, and the chemical composition mass percentage of molten iron is adjusted to: C3.90%, Si 1.16%, P≤0.04%, CE 4.30%, Cr≤0.05%, Mn 0.35%, Sn during smelting ≤0.013%, Cu0.41%, S≤0.02%, other trace elements ≤0.1%, after production and processing, the final measured chemical composition of the casting is: C 3.70%, Si 2.16%, P 0.03%, CE 4.43% , Cr 0.03%, Mn 0.35%, Sn 0.014%, Cu0.41%, AF 1.71%, S 0.009%, Mg 0.035%, RE 0.011%, other trace elements less than 0.1%.

Embodiment 3

[0040] The production method adopted is the same as in Example 1, and the chemical composition mass percentage of molten iron is adjusted to: C3.95%, Si 1.40%, P≤0.04%, CE 4.43%, Cr≤0.05%, Mn 0.30%, Sn during smelting ≤0.013%, Cu0.38%, S≤0.02%, other trace elements ≤0.1%, after production and processing, the final measured chemical composition of the casting is: C 3.75%, Si 2.40%, P 0.03%, CE 4.56% , Cr 0.029%, Mn 0.30%, Sn 0.013%, Cu0.38%, AF 1.58%, S 0.012%, Mg 0.036%, RE 0.012%, other trace elements less than 0.1%.

[0041] According to the conclusions drawn in the above-mentioned embodiment 1, embodiment 2 and embodiment 3, tabular analysis is carried out, as shown in the following table 1, table 2 and table 3.

[0042] Table 1 Spectral block analysis results

[0043]

technical field

[0001] The invention belongs to the field of casting technology and new materials, and in particular relates to high-strength and high-toughness cast QT700-10 and a production method thereof. Background technique

[0002] Ductile iron, especially high-strength and high-toughness ductile iron, is more and more widely used in the fields of construction machinery and auto parts, and many steel castings are gradually replaced by high-strength and toughness ductile iron. For some automotive safety parts, such as axle housings, steering knuckles, planetary wheel housings, differential housings, hubs, flange shafts, etc., are the main load-bearing parts, requiring parts to have high strength and good extensibility. At present, the national standard GB / T1348-2009 stipulates 15 grades for ductile iron materials, among which QT450-10, QT600-3, QT700-2 and other grades are commonly used. The former has higher elongation but lower tensile strength, and the latter The la...

Examples

Embodiment 1

[0036] Adjust the temperature of the electric furnace to 1530 ° C ~ 1550 ° C, add recarburizers and scrap steel to adjust the mass percentage of the chemical composition in the molten iron during the smelting process of the electric furnace, and adjust the chemical composition of the molten iron in the furnace to: C3.82%, Si 1.10%, P≤0.04%, CE 4.2%, Cr≤0.05%, Mn 0.40%, Sn≤0.013%, Cu 0.45%, S≤0.02%, other trace elements≤0.1%, high temperature for 8-10 minutes, Remove the slag to obtain pure molten iron; the obtained molten iron is spheroidized and inoculated, and the Sn content is adjusted. The molten iron of the above components is spheroidized, the bottom of the bag is inoculated once, and the Sn content is adjusted in the bag. The weight of the molten iron in one treatment is 750Kg , the spheroidizing treatment adopts the cover bag method, that is, the dam-type spheroidizing bag, and the bag is repaired according to the technical requirements before use, and the spheroidizing...

Embodiment 2

[0038] The production method adopted is the same as that of Example 1, and the chemical composition mass percentage of molten iron is adjusted to: C3.90%, Si 1.16%, P≤0.04%, CE 4.30%, Cr≤0.05%, Mn 0.35%, Sn during smelting ≤0.013%, Cu0.41%, S≤0.02%, other trace elements ≤0.1%, after production and processing, the final measured chemical composition of the casting is: C 3.70%, Si 2.16%, P 0.03%, CE 4.43% , Cr 0.03%, Mn 0.35%, Sn 0.014%, Cu0.41%, AF 1.71%, S 0.009%, Mg 0.035%, RE 0.011%, other trace elements less than 0.1%.

Embodiment 3

[0040] The production method adopted is the same as in Example 1, and the chemical composition mass percentage of molten iron is adjusted to: C3.95%, Si 1.40%, P≤0.04%, CE 4.43%, Cr≤0.05%, Mn 0.30%, Sn during smelting ≤0.013%, Cu0.38%, S≤0.02%, other trace elements ≤0.1%, after production and processing, the final measured chemical composition of the casting is: C 3.75%, Si 2.40%, P 0.03%, CE 4.56% , Cr 0.029%, Mn 0.30%, Sn 0.013%, Cu0.38%, AF 1.58%, S 0.012%, Mg 0.036%, RE 0.012%, other trace elements less than 0.1%.

[0041] According to the conclusions drawn in the above-mentioned embodiment 1, embodiment 2 and embodiment 3, tabular analysis is carried out, as shown in the following table 1, table 2 and table 3.

[0042] Table 1 Spectral block analysis results

[0043]

Images