CN106350654A

CN106350654A - Treatment method capable of enabling harness of steel welding joints to be uniform

Info

Publication number: CN106350654A
Application number: CN201510719449.8A
Authority: CN
Inventors: 何富银; 易群利; 刘辉
Original assignee: SICHUAN DEGREE MECHANICAL AND ELECTRICAL EQUIPMENT Co Ltd
Current assignee: SICHUAN DEGREE MECHANICAL AND ELECTRICAL EQUIPMENT Co Ltd
Priority date: 2015-07-17
Filing date: 2015-10-27
Publication date: 2017-01-25

Abstract

The invention provides a treatment method capable of enabling the harness of steel welding joints to be uniform. Steel welding pieces are subjected to normalizing heat treatment under the condition of 920 DEG C per hour and then are subjected to tempering heat treatment at 590 DEG C. The treatment method adopts a normalizing and tempering combining method, so that the aims of eliminating the welding stress of the steel welding piece and stabilizing the size of the welding piece can be fulfilled successfully, the difference between Vickers hardness values of any two points of a welding line on the same section of the steel (low-alloy steel) welding joints, a heat affected zone and a parent metal can be guaranteed to be less than or equal to 20 HV10, and the hardness of the welding line of the welding joints of the steel welding piece, the heat affected area and the parent metal is uniform, so that the requirements of a special welding structure (such as mirror plate parts in hydroelectric equipment) on the hardness uniformity of the welding joints and high size precision are met.

Description

One kind makes the uniform processing method of welded steel joint hardness

Technical field

The present invention relates to welded steel part manufacturing technology field is and in particular to one kind makes steel (low-alloy steel) The uniform processing method of welding point hardness.

Background technology

At present, for eliminating the welding residual stress of steel (low-alloy steel) weldment it is ensured that weldment dimensionally stable Property, steel weldment postwelding generally will carry out stress-removal heat treatment, especially high to dimension precision requirement weldering Fitting, is incubated 2h heat treatment usually at 590 DEG C to 640 DEG C.But stress-removal heat treatment is only capable of eliminating Welding residual stress, stablize weldment size it is impossible to ensure steel weldment welding point in weld seam, heat affected area The uniformity of hardness and between base metals, that is, it cannot be guaranteed that weld seam in welding point, heat affected area and mother metal gold Between genus, arbitrary 2 points of maximum Vickers hardness difference is less than 20hv10.

Content of the invention

It is an object of the invention to provide one kind makes the uniform processing method of welded steel joint hardness, using normalizing The means combining with tempering, make weld seam, heat affected area and base metals in the welding point of welded steel part Between hardness uniformly, the uniformity of hardness in welding point each region can be effectively ensured, and meet high size essence The requirement of degree weldment.

To achieve these goals, the technical solution used in the present invention is as follows:

One kind makes the uniform processing method of welded steel joint hardness, by welded steel part in 920 DEG C/1h just Burning hot process, then carries out tempering heat treatment at 590 DEG C.

According to above scheme, described welded steel part is low-alloy steel weldment.

According to above scheme, when the thickness of described welded steel part is less than or equal to 50mm, described tempering The temperature retention time of heat treatment is 2h.

According to above scheme, when the thickness of described welded steel part is more than 50mm, described tempering heat treatment Temperature retention time be [2+ (weldment thickness -50)/100] h.

According to above scheme, any two points between the weld seam of described welded steel part, heat affected area and base metals Between the difference of Vickers hardness number control less than or equal to 20hv10.

The invention has the beneficial effects as follows:

The present invention increases a normalizing heat treatment, i.e. normalizing to welded steel part in traditional stress-removal before processing Tempering heat treatment more afterwards, eliminates welding stress, stablizes the mesh of weldment size except can smoothly realize steel weldment Outer moreover it is possible to ensure steel (low-alloy steel) welding point with the weld seam on section, heat affected area and mother metal The difference of the Vickers hardness number between metal any two points is less than or equal to 20hv10, makes the welding of welded steel part In joint, between weld seam, heat affected area and base metals, hardness is uniform, thus meeting special welding structure (for example Runner plate part in hydroelectric facility) Welded Joints uniformity of hardness and high dimensional accuracy requirement.

Brief description

Fig. 1 be processed by the invention after test sample (specimen coding a3-2) and as-welded sample (sample Numbering a3-1) welding point (front) vickers hardness test result figure；

Fig. 2 be processed by the invention after test sample (specimen coding a3-2) and as-welded sample (sample Numbering a3-1) welding point (back side) vickers hardness test result figure；

Fig. 3 is the test sample (specimen coding a1-2) and (examination of as-welded sample after 590 DEG C/2h heat treatment Sample numbering a1-1) welding point (front) vickers hardness test result figure；

Fig. 4 is the test sample (specimen coding a1-2) and (examination of as-welded sample after 590 DEG C/2h heat treatment Sample numbering a1-1) welding point (back side) vickers hardness test result figure；

Fig. 5 is the test sample (specimen coding a2-2) and (examination of as-welded sample after 640 DEG C/2h heat treatment Sample numbering a2-1) welding point (front) vickers hardness test result figure；

Fig. 6 is the test sample (specimen coding a2-2) and (examination of as-welded sample after 640 DEG C/2h heat treatment Sample numbering a2-1) welding point (back side) vickers hardness test result figure.

Specific embodiment

With embodiment, technical scheme is illustrated below in conjunction with the accompanying drawings.

The present invention provides one kind to make the uniform processing method of welded steel joint hardness, by thickness for 40mm's Low-alloy steel weldment, in 920 DEG C/1h normalizing heat treatment, then carries out tempering heat treatment in 590 DEG C/2h.

In order to verify the effect of the present embodiment, also the weldment of same material, same weld technique is existed respectively 590 DEG C/2h tempering heat treatment, 640 DEG C/2h tempering heat treatment, do not carry out post weld heat treatment (i.e. as-welded aw) Sample, carry out Vickers hardness comparative determination, measurement result such as Fig. 1 to Fig. 6 together with the present embodiment sample Shown.

Test result from Fig. 1 to Fig. 2 can be seen that after processing through the present embodiment Weld seam on same section for the test sample (specimen coding a3-2) of (920 DEG C/1h+590 DEG C/2h), On heat affected area and base metals, the hv10 difference of hardness of any two points is reduced to≤14hv10, fully meets and appoints Anticipate the technical requirements of two point hardness differences≤20hv10.

Test result from Fig. 1 to Fig. 6 is not it can also be seen that carry out the test sample of heat treatment after welding , there is tissue and the extremely uneven welding heat affected zone of performance in (specimen coding a1-1, a2-1, a3-1), Hardness peak occurs in heat affected area, reaches with hv10 hardness maximum difference on section in test sample 91hv10 is it is impossible to meet the technical requirements of any two points difference of hardness≤20hv10.

Test result from Fig. 3 to Fig. 4 can be seen that the (examination of the test sample after 590 DEG C/2h heat treatment Sample numbering a1-2), although the tissue of weldment welding point and performance are more uniform than as-welded, Vickers hardness is also Reduce, but the hardness of base metals is declined slightly, and the average hardness level of weld metal zone and heat affected area have bright Aobvious reduction, in the upper hv10 hardness in the same section of sample (including weld metal zone, heat affected area and base metals) Big difference drops to 57hv10, but still can not meet the technical requirements of any two points difference of hardness≤20hv10.

Test result from Fig. 5 to Fig. 6 can be seen that the (examination of the test sample after 640 DEG C/2h heat treatment Sample numbering a2-2), welding point can decline further with the hv10 difference of hardness on section, under maximum difference Drop to 47hv10 hardness.But the Vickers hardness between any two points is poor in weld seam, heat affected area and base metals ≤ the technical requirements of 20hv10 still can not be met.

The present invention adopts in 920 DEG C/1h normalizing heat treatment, then in 590 DEG C/2h tempering heat treatment, metal group Solid-state phase changes are given birth in hair-weaving, and the crystal grain of its weld dimensions is refined, weld seam, the tissue of heat affected area Reach unanimity with the tissue of mother metal, be tempered again after normalizing and can substantially reduce stress, stable dimensions, acceptable It is obviously improved the uniformity (particularly hardness) of tissue and performance.Therefore, weldment through normalizing add-back fire after, Its tissue and performance more uniform, the average hardness level of Seam and heat effected zone declines further, and with mother Material metal reaches unanimity.

Above example is only in order to illustrative and not limiting technical scheme, although above-described embodiment is to this Invention has been described in detail, and the person skilled of this area is it is understood that can repair to the present invention Change or replace on an equal basis, but any modification without departing from spirit and scope of the invention and local are replaced and all should be covered In scope of the presently claimed invention.

Claims

1. one kind makes the uniform processing method of welded steel joint hardness it is characterised in that by welded steel part In 920 DEG C/1h normalizing heat treatment, at 590 DEG C, then carry out tempering heat treatment.

2. according to claim 1 make the uniform processing method of welded steel joint hardness, its feature exists In described welded steel part is low-alloy steel weldment.

3. according to claim 1 make the uniform processing method of welded steel joint hardness, its feature exists In when the thickness of described welded steel part is less than or equal to 50mm, during the insulation of described tempering heat treatment Between be 2h.

4. according to claim 1 make the uniform processing method of welded steel joint hardness, its feature exists In when the thickness of described welded steel part is more than 50mm, the temperature retention time of described tempering heat treatment is [2+ (weldment thickness -50)/100] h.

5. according to claim 1 make the uniform processing method of welded steel joint hardness, its feature exists In the Vickers hardness number between any two points between the weld seam of described welded steel part, heat affected area and base metals Difference control less than or equal to 20hv10.