CN1169972C - Heat treating process and inductor for key surface of hub - Google Patents

Abstract

The present invention discloses a heat treatment method of key surface of a wheel hub unit, and an inductor of a heat treatment method of key surface of a wheel hub unit. The method comprises: a workpiece to be quenched is put into the inductor, heated by a medium-frequency induction heater and quenched in a high-power short-time internal water spraying method, the radial clearance between the workpiece and an upper induction coil is from 5 to 10 millimeters, the radial clearance between the workpiece and a lower induction coil is from 3 to 5 millimeters, and the axial clearance is from 1.5 to 2.5 millimeters. The inductor comprises two current conductors, the upper induction coil and the lower induction coil, wherein the outer part of the lower induction coil is provided with a magnetic conductor; the upper induction coil and the lower induction coil are respectively two semicircles. The present invention has the advantages that the inductor for the induction heating of the workpiece surface is easily fabricated, and the inductor in the form, which only correspondingly changes the geometric dimension, can be suitable for the surface induction quenching of all the similar parts; the novel inductor does not have the obvious sharp corner effect so that stepped transition zones with different shaft diameters and flanged disc roots with different shaft diameters can obtain ideal quench-hardened layers; the inductor has low requirements for the accuracy of a quenching machine tool and the accuracy of a clamp for parts.

Description

Hub critical surfaces heat treating method and inductor block thereof

Technical field

The present invention relates to a kind of hub critical surfaces heat treating method and inductor block thereof.

Background technology

Hub is the high technology content of developing in recent years, the auto-parts of high added value, it is vapour axle company's new growth engines and developing direction, particularly company just discusses the supporting matters of third generation hub with global maximum auto parts machinery supplier DELPHI at present, therefore the hub trial-manufacture of sample is the task of top priority, and the surface heat processing is a hub manufacturing critical process; Particularly the surface heat treatment process difficulty of DELPHI part 7467101/03 is big, requirement is high, becomes the DELPHI project and develops bright critical bottleneck technology.

One, DELPHI project part 7467101/03 critical process surface is heat treated will ask for an interview to Fig. 1, is described as follows:

The A place: flange root quench-hardened case diameter reaches the requirement of Φ 64～74;

Locate for B45 °: require quench-hardened case DS=2.25～4.0, hardened layer hardness is HRC58～64;

The C ditch is directly located: require depth of hardening zone DS=2.75～6.0, hardened layer hardness is HRC60～64;

D diameter place: depth of hardening zone DS=1.0～2.0, hardened layer hardness is greater than HRC45;

E place: the minimum 8mm of being of the distance of not hardening.

Two, critical technological point analysis

1, the part head is very thin, easily heat penetration; Two step wedge angles and head seamed edge are overheated easily;

2, the flange root filtrating area (raceway groove) different with diameter is to be difficult for heating region, and requires to obtain darker quench-hardened case;

3, B, C, D place depth of hardening zone require to differ;

4, whole surface requirements once heats and quenches simultaneously and obtain the successive hardened layer;

By above critical technological point analysis as can be known: adopting traditional quenching technology for surfaces and heating principle commonly used is to be difficult to meet the requirements of,

Three, inductor block

1, by traditional technology---longitudinal magnetic flux heating method commonly used, manufactured and designed a cone-type spiral inductor block, be characterized in that induced current is along workpiece circumferential direction distribution (seeing Fig. 3, the sense of current 1, inductor block 2, workpiece 3 among the figure).

Test-results is that sharp angle effect is strong, and step seamed edge and head are grilled thoroughly, and workpiece flange root and raceway groove (step axle zone of transition) are not heated to technological temperature.This scheme of evidence is not all right.

2, the method that adopts longitudinal magnetic flux and transverse magnetic flux to combine manufactures and designs inductor block, be characterized in the induced current part along workpiece circumferential direction part along workpiece axial direction due (see figure 4).

This method has solved the heating problems of workpiece flange root through test, the raceway groove heating of workpiece also can but the degree of depth is not enough, do not reach the drawing requirement, this scheme of evidence is also not all right.

Summary of the invention

The invention provides a kind of hub critical surfaces heat treating method and inductor block thereof.

Hub critical surfaces heat treating method is that workpiece to be quenched is put into inductor block, heat by medium frequency induction heater, adopt high-power, short period of time, interior water spray means to quench, workpiece and last ruhmkorff coil radius clearance are 5～10 millimeters, with the radius clearance of following ruhmkorff coil be 3～5 millimeters, end play is 1.5～2.5 millimeters.

The inductor block that is used for the surface induction heating has two baffles, last ruhmkorff coil, following ruhmkorff coil, be provided with magnetizer outside the ruhmkorff coil down, upper and lower ruhmkorff coil is respectively two semicircles, one baffle is successively with following ruhmkorff coil left semicircle, last ruhmkorff coil left semicircle, ruhmkorff coil right semi-circle, last ruhmkorff coil right semi-circle and another baffle are interconnected down, and water flowing.

Advantage of the present invention: 1, the inductor block of workpiece surface induction heating is made easily, and the inductor block of this form is only made the surface induction hardening that corresponding change can adapt to all like parts to geometrical dimension.2, novel inductor does not have tangible sharp angle effect, and the step transition district and the ring flange root of the different diameters of axle all can obtain the ideal quench-hardened case.3, not high to quenching machine and part clamp accuracy requirement.

Description of drawings

Fig. 1 is 7467101/03 sketch and the requirement of surface heat treatment technology;

Fig. 2 is the graph of a relation of quench-hardened case and heat-up time;

Fig. 3 is a longitudinal magnetic flux heating schematic diagram;

Fig. 4 is a vertical, horizontal magnetic flux heating schematic diagram;

Fig. 5 is a transverse magnetic flux heating schematic diagram;

Fig. 6 is the magnetizer structure dimensioned drawing;

Fig. 7 is the sensor structure sectional view;

Fig. 8 is the vertical view of inductor block.

Embodiment

Hub critical surfaces heat treating method is that workpiece to be quenched is put into inductor block, heat by medium frequency induction heater, adopt high-power, short period of time, interior water spray means to quench, workpiece and last ruhmkorff coil radius clearance are 5～10 millimeters, with the radius clearance of following ruhmkorff coil be 3～5 millimeters, end play is 1.5～2.5 millimeters.

The inductor block that is used for the surface induction heating has two baffles 4, last ruhmkorff coil 5, following ruhmkorff coil 6, be provided with magnetizer 7 outside the ruhmkorff coil down, upper and lower ruhmkorff coil is respectively two semicircles, one baffle is successively with following ruhmkorff coil left semicircle, last ruhmkorff coil left semicircle, ruhmkorff coil right semi-circle, last ruhmkorff coil right semi-circle and another baffle are interconnected down, and water flowing.

Said upper and lower ruhmkorff coil is square special-shaped copper pipe.Following ruhmkorff coil diameter is greater than last ruhmkorff coil diameter.Magnetizer is the siliconized plate of δ=0.1～0.35 millimeter.

Four, process exploitation process

1, the selection of device frequency

According to data, frequency is selected to be calculated as follows when induction heating rotator, plane body:

$f=\frac{5\×{10}^4}{{\mathrm{\δ}}^2}$

Get δ=2.5mm, then

$f=\frac{{5\×10}^4}{{\mathrm{\δ}}^2}=8000\mathrm{HZ}$

The calculation specifications hard surfacing adopts intermediate frequency power supply more suitable.

2, power calculation

According to the method for calculation that data is introduced, part heating total power consumption:

Q＝ΔQ.S

Wherein, Δ Q=5kw.s/cm ²(the unit consumption of energy consumption has been considered various losses)

S---the surface-area of part heating

The surface-area of part heating is divided into four parts, is calculated as follows:

S＝S ₁+S ₂+S ₃+S ₄

$S_1=\mathrm{\π}.{\left(\frac{7.4}{2}\right)}^2-\mathrm{\π}{\left(\frac{5.0}{2}\right)}^2=24.22{\mathrm{cm}}^2$

S ₂＝12×π×38＝14cm ²

S ₃＝24×π×43＝32.4cm ²

S ₄＝12×π×50＝18.8cm ²

S＝24.22+14+32.4+18.8＝89.4cm ²

Q＝5kw.s/cm ²×89.4cm ²＝447kw.s

Introduce the graph of a relation (see figure 2) of quench-hardened case and heat-up time by data, find: DS=2.5mm corresponding heat-up time is 3 seconds (DELPHI requires not too wide zone of transition of quench-hardened case core metal, and will lack selected heat-up time), and then rated output is:

$P_0=\frac{Q}{t}=\frac{447\mathrm{kw}.s}{3s}=149\mathrm{kw}$

Select to be greater than 150kw according to the calculation result plant capacity, promptly equipment choosing power 150kw or 200kw all can.

3, sensor structure design

All adopt the transverse magnetic flux heating method to manufacture and design the inductor block (see figure 5).Be characterized in inductive current direction along the workpiece axial direction due, workpiece step seamed edge and head corner angle sharp angle effect are very little, and step axle filtrating area (raceway groove) and workpiece surface distribution of current are even; In order to make workpiece flange root obtain same rate of heating, increased by row's magnetizer near circle under the inductor block of workpiece flange root, material is selected the siliconized plate (reality substitutes with δ=0.5mm) of δ=0.1～0.35mm for use according to data.Magnetizer adopts the line cutting processing, and scantlings of the structure is seen Fig. 6.

Inductor block and workpiece radius clearance are 3mm, with the Flange Plane gap be 2mm, concrete structure size See Attachment 1 sensor structure figure.

4, technological test

Adopt novel inductor, heat test just finds that each position of workpiece comprises ring flange root, raceway groove (step axle zone of transition), excircle of workpiece surface homogeneous heating for the first time.Find the head through hardening by cutting sample, analyze discussion through us and solved this problem at the head endoporus refrigerative technological measure of taking to spray water.

Five, quality examination

Check result reaches the drawing requirement fully and meets DELPHI standard HTS004.(, and there is not the induction quenching metallographic examination standard of 1070 steel correspondences at present because DELPHI standard HTS004 metallographic structure does not have classification; And the chemical ingredients of 1070 steel is similar to 65Mn, so use People's Republic of China's specialized standard, standard No.: ZB J36009-98, standard name: steel part induction quenching metallographic examination, applicability of standard: the mechanical component that medium carbon structure iron and medium carbon structural alloy steel are made, the check of metallographic structure and effective case depth behind height, mid-frequency induction hardening.)

Six, conclusion

1, the inductor block that manufactures and designs of transverse magnetic flux heating method is through facts have proved: the sharp angle effect in the time of can reducing hard surfacing, and the step axle filtrating area of the different diameters of axle can obtain the ideal quench-hardened case;

2, DELPHI workpiece 7467101/03 quenching technology for surfaces can promote the use of all similar workpiece of third generation hub.

Claims (5)

1. hub critical surfaces heat treating method, it is characterized in that workpiece to be quenched is put into inductor block, heat by medium frequency induction heater, adopt high-power, short period of time, interior water spray means quenches, workpiece and last ruhmkorff coil radius clearance are 5～10 millimeters, with the radius clearance of following ruhmkorff coil be 3～5 millimeters, end play is 1.5～2.5 millimeters, said inductor block has two baffles [4], last ruhmkorff coil [5], following ruhmkorff coil [6], be provided with magnetizer [7] outside the ruhmkorff coil down, on, following ruhmkorff coil is respectively two semicircles, one baffle successively with following ruhmkorff coil left semicircle, last ruhmkorff coil left semicircle, following ruhmkorff coil right semi-circle, last ruhmkorff coil right semi-circle and another baffle are interconnected, and water flowing.

2. one kind is used for the inductor block that surface induction heats, it is characterized in that it has two baffles [4], last ruhmkorff coil [5], following ruhmkorff coil [6], be provided with magnetizer [7] outside the ruhmkorff coil down, upper and lower ruhmkorff coil is respectively two semicircles, one baffle is successively with following ruhmkorff coil left semicircle, last ruhmkorff coil left semicircle, ruhmkorff coil right semi-circle, last ruhmkorff coil right semi-circle and another baffle are interconnected down, and water flowing.

3. a kind of inductor block that is used for the surface induction heating according to claim 2 is characterized in that said upper and lower ruhmkorff coil is square special-shaped copper pipe.

4. according to claim 2 or 3 described a kind of inductor blocks that are used for the surface induction heating, it is characterized in that said ruhmkorff coil diameter down is greater than last ruhmkorff coil diameter.

5. a kind of inductor block that is used for surface induction heating according to claim 2 is characterized in that said magnetizer is the siliconized plate of δ=0.1～0.35 millimeter.

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