CN112210653A

CN112210653A - Heat treatment quenching method for high-precision space curve track type parts

Info

Publication number: CN112210653A
Application number: CN202011043762.1A
Authority: CN
Inventors: 傅在再
Original assignee: Chongqing Changan Industry Group Co Ltd
Current assignee: Chongqing Changan Industry Group Co Ltd
Priority date: 2020-09-28
Filing date: 2020-09-28
Publication date: 2021-01-12

Abstract

A heat treatment quenching method for high-precision space curve track parts includes such steps as assembling the high-precision space curve track parts by multi-point fastening quenching fixture, tightly fixing the high-precision space curve track parts by twenty special bolts, quenching, fixing high-precision space curve track type parts on a special cylinder (1) by using a special bolt (2) and a special nut (3), placing the whole clamp and the parts in a vacuum furnace material frame, carrying out heating quenching in a vacuum furnace and low-temperature tempering in a pit furnace, then placing the whole fixture and the parts in an oil furnace for low-temperature long-time tempering, and taking the materials out of the furnace, placing the materials for 48 hours, and then disassembling the special bolt (2) and the special nut (3) and taking out the space curve track type parts. The invention can greatly reduce the distortion of high-precision space curve track parts during quenching.

Description

Heat treatment quenching method for high-precision space curve track type parts

Technical Field

The invention belongs to the technical field of heat treatment quenching, and particularly relates to a heat treatment quenching method for high-precision space curve track parts.

Background

The processing process of the space curve track type part made of the ultrahigh-strength steel such as 30CrNi2MoVE and the like comprises the steps of firstly carrying out heat treatment quenching and tempering on a semi-finished circular tubular part, namely heating the semi-finished circular tubular part to an AC1 temperature line to obtain austenite, then carrying out oil cooling quenching on the circular tubular part to obtain martensite, carrying out low-temperature tempering on the part to obtain tempered martensite, controlling the hardness of the circular tubular part to be 45HRC-50HRC high-hardness high-strength state, and finally processing the part in the high-hardness high-strength state by adopting a special mechanical processing method and using an expensive super-hardness cutter to obtain the space curve guide rail with certain precision requirement. The machining tool is easy to break, severe in abrasion, low in service life and very high in machining cost.

The second processing route of the space curve rail type part is that heat treatment quenching and tempering is carried out when a semi-finished product is in a round tubular shape, the quenching and tempering hardness is controlled to be 28HRC-36HRC, then the part is processed to a high-precision finished product part by common machining means such as turning and milling, then the high-precision finished product part is subjected to heat treatment quenching and low-temperature tempering without any equipment free state, a finished product with the hardness of 45HRC-50HRC and a tempered martensite metallographic structure is obtained, for the space curve rail type part, the part is greatly deformed and twisted in the quenching mode, and the part after heat treatment quenching basically has no qualified possibility.

As can be gathered from the above two general process approaches, the first is expensive to manufacture and the second is technically infeasible.

Disclosure of Invention

The invention aims to overcome the problems in the prior art and provide a heat treatment quenching method for high-precision space curve rail parts.

The invention relates to a heat treatment quenching method for high-precision space curve track parts, which adopts a space multipoint fastening quenching clamp, wherein the clamp consists of a specially-made cylinder 1, a special bolt 2 and a special nut 3, before the high-precision space curve track parts after machining are subjected to vacuum heat treatment, the high-precision space curve track parts are assembled by using the space multipoint fastening quenching clamp, the high-precision space curve track parts are tightly fixed on the circumference of the specially-made cylinder clamp by twenty specially-made bolts, and the distortion of the high-precision space curve track parts during quenching is restrained by the space multipoint fastening quenching clamp;

during quenching, the high-precision space curve track type part is fixed on a special cylinder 1 through a special bolt 2 and a special nut 3, the whole fixture and the part are placed in a vacuum furnace material frame, heating quenching and well furnace low-temperature tempering are carried out on the fixture and the part, the fixture and the part are placed in an oil furnace for low-temperature long-time tempering, the fixture and the part are discharged from the furnace and placed for 48 hours, the special bolt and the special nut can be disassembled, and the space curve track type part is taken out.

The invention has the beneficial effects that: the distortion of the high-precision space curve track type part after heat treatment and quenching is very small, and the machining cost of the part is low.

Drawings

Fig. 1 is an assembly drawing of a space multi-point fastening quenching fixture.

FIG. 2 is a drawing of a special cylinder.

Fig. 3 is a view of the special cylinder A.

Fig. 4 is a view of the special cylinder in the direction B.

Fig. 5 is a front view of the special nut.

Fig. 6 is a view of the special nut C.

Fig. 7 is a front view of the special bolt.

Fig. 8 is a view of the special bolt D.

In the above figures: 1 special cylinder, 2 special nut and 3 special bolt.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

Examples

In the embodiment, a spatial multi-point fastening quenching clamp is adopted to quench No. 02-4/5 parts in certain products II-55 of our company in a name curve groove, and the spatial multi-point fastening quenching clamp is assembled as shown in figure 1, wherein the part figures are shown in figure 2, figure 3 and figure 4; fig. 5, fig. 6, fig. 7, fig. 8; fig. 2 is a front view of a tailored cylinder (1), wherein: position coordinates (angle, Y) of the hole: 10(312 °, 33), 9(280 °, 78), 8(228 °, 166), 7(228 °, 207), a5(228 °, 357), a6(228 °, 310), a7(248 °, 257) a8(280 °, 178). The size tolerance of the outer circle of the special cylinder (1) is matched with the size tolerance of the inner circle of the assembled curve groove,

FIG. 3 is a view of the special cylinder (1) A, marked with the external diameter phi 172h10(⁰ _-0.16) (ii) a Fig. 4 is a view of the tailored cylinder (1) in the direction B, with the position coordinates (angle, Y) of the holes: a4(150 °, 357), a3(106 °, 257), a2(74 °, 166), a1(35 °, 78),6(175 °, 310), 5(150 °, 257), 4(106 °, 135), 3(85 °, 78), 2(74 °, 33), 1(60 °, 33).

The curve groove is plugged into a specially-made cylinder (1), 20 special bolts (3) and 20 special nuts (2) are used for fastening the curve groove, so that the curve groove is tightly attached to the surface of a specially-made cylindrical clamp (1), a torque wrench is used for enabling the tightening force of each nut to reach 75NM, and the clamp is used for forcedly fixing to limit the deformation of the curve groove in the heating and quenching processes; placing the clamp with the assembled curve groove in a material frame of a vacuum furnace, pushing the material frame into a front chamber of the vacuum furnace, fixing the material frame by using a bolt, moving down a pushing arm at the inner side of the front chamber of the vacuum furnace, closing a furnace door of the vacuum furnace, and operating according to the furnace opening step of the vacuum furnace to finish the heating and quenching process and the tempering process of the vacuum furnace of the No. 02-4/5 part; the material selection of the special cylindrical clamp (1), the special bolt (3) and the special nut (2) must be the same as the material 30CrNi2MoVA of the curve groove, so that when the curve groove is assembled and fixed on the special cylindrical clamp, the expansion coefficients of the curve groove and the special bolt are the same, the heating expansion and the cooling contraction are carried out synchronously, and the special cylindrical clamp is beneficial to reducing the heat treatment deformation of the curve groove.

Claims

1. A heat treatment quenching method for high-precision space curve track parts is characterized by comprising the following steps: before the machined high-precision space curve track type part is subjected to vacuum heat treatment, assembling the high-precision space curve track type part by using a space multipoint fastening quenching clamp, tightly fixing the high-precision space curve track type part on the circumference of a special cylindrical clamp by using twenty special bolts, and restraining the distortion of the high-precision space curve track type part during quenching by using the space multipoint fastening quenching clamp; the space multipoint fastening quenching fixture is composed of a special cylinder (1), a special bolt (2) and a special nut (3), when in quenching, a high-precision space curve track part is fixed on the special cylinder (1) through the special bolt (2) and the special nut (3), the whole fixture and the part are placed in a vacuum furnace material frame to be heated and quenched by a vacuum furnace and tempered at a low temperature by a pit furnace, then the whole fixture and the part are placed in an oil furnace to be tempered at a low temperature for a long time, and then the special bolt (2) and the special nut (3) can be disassembled after being taken out of the furnace and placed for 48 hours, and the space curve track part is taken out.