Heat treatment shaping method for high-strength, high-toughness and high-elasticity GH578 alloy coil spring

Abstract

The invention belongs to the field of coil spring heat treatment, and particularly relates to a heat treatment shaping method for a high-strength, high-toughness and high-elasticity GH578 alloy coil spring. According to the technical scheme, the heat treatment shaping method for the high-strength, high-toughness and high-elasticity GH578 alloy coil spring comprises the steps that the high-strength, high-toughness and high-elasticity GH578 alloy coil spring is clamped through a heat treatment shaping clamp, and then heat treatment is conducted; the heat treatment shaping clamp comprises a round clamping ring and a crescent-shaped positioning pin, the coil spring is screwed and placed in the round clamping ring, the crescent-shaped positioning pin is nailed in a gap between rings of the coil spring, and it is guaranteed that the gap between the inner rings of the coil spring is large, and the gap between the outer rings of the coil spring is small. According to the heat treatment shaping method for the high-strength, high-toughness and high-elasticity GH578 alloy coil spring, stable heat treatment shaping of the coil spring is achieved through the heat treatment shaping clamp, the design structure and elasticity requirements of the coil spring are guaranteed, the manufacturing qualification rate of coil spring parts is increased, and the manufacturing cost is reduced.

Description

Technical Field

[0001] The invention belongs to the field of coil spring heat treatment, and specifically relates to a heat treatment shaping method for a high-strength, high-toughness and high-elasticity GH578 alloy coil spring. Background Art

[0002] Coil springs are mainly used in aircraft engine control systems. They are elastic components installed in the nozzle and connected to the sensor through a rocker arm. They are mainly subjected to torsion force and the operating temperature does not exceed 200°C. The elastic force of the coil spring is used to ensure a fixed gap between the nozzle and the sensor. When the aircraft engine is in operation, the coil spring is always under force.

[0003] The high-strength, high-elastic modulus nickel-chromium-cobalt-based GH578 alloy adopts a variety of strengthening measures: high-content W (W ≥ 9%) solid solution strengthening, high-content Al and Ti (Al + Ti ≥ 4%) dispersion strengthening and cold deformation strengthening before aging; cold deformation also further promotes the precipitation of γ′ phase during aging; this alloy has high strength and high elastic modulus that general elastic high-temperature alloys cannot match, making it an ideal material for manufacturing coil springs.

[0004] Due to the special shape of the coil spring of the aircraft engine, such as the attached Figure 1 As shown, a larger deformation space is required, and the gaps between each circle are not equal. The inner circle gap is large, and the outer circle gap is small, which violates the deformation law. At the same time, the outer diameter is limited. Therefore, the parts are very easy to deform during heat treatment. Summary of the invention

[0005] The invention provides a heat treatment shaping method for a high-strength, high-toughness and high-elasticity GH578 alloy coil spring, which realizes the stabilized heat treatment shaping of the coil spring through a heat treatment shaping fixture, ensures the design structure and elastic force requirements of the coil spring, improves the manufacturing qualification rate of coil spring parts, and reduces the manufacturing cost.

[0006] The technical solution of the present invention is as follows:

[0007] A heat treatment shaping method for a high-strength, high-toughness and high-elasticity GH578 alloy coil spring, which comprises a heat treatment shaping fixture for clamping the high-strength, high-toughness and high-elasticity GH578 alloy coil spring and then performing heat treatment; the heat treatment shaping fixture comprises a circular clamping ring and a crescent-shaped positioning pin, the coil spring is tightened and placed in the circular clamping ring, and the crescent-shaped positioning pin is nailed into the gap between the coil spring circles to ensure that the inner circle gap of the coil spring is large and the outer circle gap is small.

[0008] Furthermore, in the heat treatment shaping method of the high-strength, high-toughness and high-elasticity GH578 alloy coil spring, the wall thickness of the circular clamping ring is 8 to 10 mm.

[0009] Furthermore, in the heat treatment shaping method of the high-strength, high-toughness and high-elasticity GH578 alloy coil spring, the outer diameter of the coil spring installed in the circular clamp ring is the outer diameter of the coil spring in the free state specified in the design drawing.

[0010] Furthermore, in the heat treatment shaping method of the high-strength, high-toughness and high-elasticity GH578 alloy coil spring, the shape of the crescent-shaped locating pin matches the curvature of the inner circle of the coil spring.

[0011] Furthermore, the heat treatment shaping method of the high-strength, high-toughness and high-elasticity GH578 alloy coil spring adopts a vacuum furnace for heat treatment, keeps the temperature at 800±10℃ for 1h~1h15min, cools the furnace to 700±10℃ and keeps the temperature for 2h~2h15min, and cools with argon gas.

[0012] The beneficial effects of the present invention are as follows: the present invention realizes the stabilization heat treatment shaping of the coil spring through the heat treatment shaping fixture, ensures the design structure and elastic force requirements of the coil spring, and increases the manufacturing qualification rate of the coil spring parts from 70% to more than 95%, solving the problem that the spiral curve of the high-strength, high-toughness and high-elasticity alloy coil spring deviates from the design shape and the elastic force is unqualified after heat treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is the coil spring parts diagram;

[0014] Figure 2 This is a part drawing of a circular clamp ring;

[0015] Figure 3 This is the part drawing of crescent-shaped locating pin;

[0016] Figure 4 A diagram showing the coil spring being clamped in the heat treatment fixture. DETAILED DESCRIPTION

[0017] like Figure 1-4 As shown, a heat treatment shaping method for a high-strength, high-toughness and high-elasticity GH578 alloy coil spring, the composition and mass fraction of the GH578 alloy are as follows: V: ≤0.2%, Nb: ≤0.2%, Cu: ≤0.07%, Fe: ≤1.0%, Si: ≤0.40%, W: 9.0% to 10.5%, P: ≤0.015%, Cr: 18.0% to 20.0%, Co: 5.5% to 6.7%, Ti: 2.7% to 3.2%, Al: 1.3% to 1.8%, Mn: ≤0.40%, C: ≤0.05%, S: ≤0.010%, Sb: ≤0.001%, Sn: ≤0.002%, As: ≤0.005%, Pb: ≤0.001%, Bi: ≤0.0001%, Ni: the rest; comprising the following steps:

[0018] 1) Clean and clamp the coil spring; clean the coil spring with anhydrous ethanol, and clamp the coil spring into the circular clamp ring to ensure its fit with the circular clamp ring;

[0019] 2) Nail in the crescent-shaped locating pin; Nail the crescent-shaped locating pin into the gap between the coils of the coil spring;

[0020] 3) Vacuum aging heat treatment; perform vacuum aging heat treatment on the clamped heat treatment fixture and coil spring; use a vacuum furnace, keep the temperature at 800±10℃ for 1h~1h15min, cool the furnace to 700±10℃ and keep the temperature for 2h~2h15min, and cool with argon gas.

[0021] 4) Use pliers to repair the appearance; after removing the coil spring, grind the appearance according to the requirements of the drawing.

[0022] The average coil spring torque is 12.50 N·m.

Claims

1. A heat treatment shaping method for high-strength, high-toughness and high-elasticity GH578 alloy coil spring, characterized in that: A high-strength, high-toughness and high-elasticity GH578 alloy coil spring is clamped by a heat treatment forming fixture and then heat treated; the heat treatment forming fixture includes a circular clamp ring and a crescent-shaped positioning pin, the coil spring is tightened and placed in the circular clamp ring, and the crescent-shaped positioning pin is nailed into the gap between the coil spring circles to ensure that the inner circle gap of the coil spring is large and the outer circle gap is small.

2. The heat treatment shaping method of the high-strength, high-toughness and high-elasticity GH578 alloy coil spring according to claim 1 is characterized in that: The wall thickness of the circular clamping ring is 8 to 10 mm.

3. The heat treatment shaping method of the high-strength, high-toughness and high-elasticity GH578 alloy coil spring according to claim 1 is characterized in that: The outer diameter of the coil spring installed in the circular clamp ring is the outer diameter of the coil spring in the free state specified in the design drawing.

4. The heat treatment shaping method of the high-strength, high-toughness and high-elasticity GH578 alloy coil spring according to claim 1 is characterized in that: The shape of the crescent-shaped positioning pin matches the curvature of the inner circle of the coil spring.

5. The heat treatment shaping method of the high-strength, high-toughness and high-elasticity GH578 alloy coil spring according to claim 1 is characterized in that: The heat treatment is carried out in a vacuum furnace, kept at 800±10℃ for 1h~1h15min, cooled to 700±10℃ for 2h~2h15min, and cooled with argon gas.

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