CN117381328A - Local processing and removing method for hyperboloid depth weld defects - Google Patents

Abstract

The invention discloses a local processing and clearing method for double-curved-surface depth weld defects, which comprises the steps of firstly scribing transverse and circumferential central lines and surface processing boundary reference lines of a groove to be repaired and welded on the outer surface of a workpiece through the positions of the weld defects, then clamping and aligning the workpiece, firstly processing an arc-shaped groove by adopting a gang drill method, then milling the slopes of two sides of the arc-shaped groove, removing the left sharp corners of a twist drill, grinding the bottom of the arc-shaped groove, then checking the defect display condition of the bottom of the arc-shaped groove by adopting layered processing and layered visual observation in the depth direction until the defect is cleared, processing the arc-shaped groove into the groove to be repaired and welded, then processing the stepped slopes of two ends of the groove to be repaired and grinding all surfaces of the groove to be repaired and welded finally, so as to finish the local processing and clearing of the weld defects.

Description

Local processing and removing method for hyperboloid depth weld defects

Technical Field

The invention belongs to the technical field of pressure vessel manufacturing, and particularly relates to a local processing and cleaning method for hyperboloid depth weld defects.

Background

The pressure vessel is key equipment in a modern chemical process system, is widely applied to the fields of petrochemical industry, energy, military industry, scientific research and the like, and is core equipment for encouraging autonomous production in China. The equipment of the type often operates in severe environments such as high temperature, high pressure, low temperature, corrosion and the like, and the quality of single equipment is directly related to the safe operation of the whole process line, even the environmental safety and the life and property safety of people. And with the continuous improvement of equipment manufacturing capability, higher requirements are placed on the pressure vessel manufacturing capability and the pressure vessel manufacturing quality.

A certain key device in the reactor coolant system of the nuclear power station is a vertical cylindrical high-temperature and high-pressure container manufactured by welding low-alloy steel forgings, and because the quality of welding seams is critical to the normal operation of the process system of the whole reactor, all main pressure-bearing welding seams are required to be subjected to nondestructive detection of VT, MT, RT and UT according to relevant standards, and the requirements of 1 grade are met.

When a hyperboloid depth weld defect problem is detected, for example: when welding a certain embedded valve filler neck component and a thick-wall spherical end socket of equipment is finished and polished to be specified by a drawing and then subjected to nondestructive detection, VT, MT and RT results all meet the technical requirements and no recordable defect is found, the UT result finds an unacceptable non-volumetric defect signal to display, the defect is Zhou Xiangchang mm along a welding line, is transversely close to a welding line groove of the spherical end socket, is 85.3mm deep from the outer surface, and needs to repair the welding defect according to the program specification, but has the following technical difficulties:

(1) One of the key points of the repair treatment of the welding defect is to ensure the complete removal of the defect, but as the welding defect of the welding seam of the valve filler neck assembly and the spherical head is the non-volumetric defect found by UT, the defect is not found by repeated ray review at different angles, whether the defect is completely removed after the grooving cannot be verified by RT, and whether the defect is completely removed once the grooving is completely removed due to multi-interface reflection UT cannot be verified. If repair welding is performed in the case where the defect has not been completely removed, it is necessary to cause a secondary or even multiple repair of the weld. Therefore, the key to repair the weld defect is that the defect must be successfully found and cleaned during the defect removal process.

(2) The depth of the weld defects found by inspection from the outer surface of the weld is 85.3mm, although the depth of the weld defects from the outer surface of the weld is relatively shallow from the inner surface of the weld, the defect removal difficulty is increased because the accurate positions of the weld defects cannot be determined from the inner surface of the weld by using UT under the influence of the inner wall surfacing layer, and meanwhile, the procedures are increased because repair surfacing is performed on the local area of the inner wall again after the weld is removed from the inner side and repair welded, so that the defect removal and repair welding depth is large. In addition, the defects are positioned in the welding lines of the valve filler neck assembly and the spherical sealing head with the hyperboloid structure, and the hot working methods such as carbon arc gouging and the like are not allowed to be adopted in the technology, if the conventional angle grinder grinding method is adopted to clean the defects of the hyperboloid welding lines, the defects are not only low in efficiency, but also excessive base materials are removed, and particularly when the defects are deep, repair welding lines are seriously deviated from original welding line areas to influence the in-service inspection of equipment welding lines. It is therefore necessary to develop a machining method that eliminates the defects of the hyperboloid depth weld.

(3) The defect of the weld joint found by inspection is close to the groove of the spherical end socket in the transverse direction of the weld joint and has larger depth, meanwhile, the width of the weld joint is not excessively enlarged in the technical aspect, in order to avoid that the deep, narrow and short grooves to be repaired are formed after the defect is cleared to influence the subsequent repair welding operation, the grooves to be repaired are of an arc-shaped structure taking the transverse direction and the circumferential direction of the defect as the center, the bottoms of the grooves to be repaired are provided with the width suitable for double-channel welding and the length suitable for arc starting staggering, and the two side surfaces and the two end surfaces are required to have proper gradients and are in smooth transition with the bottoms through circular arcs. The groove to be repair welded is complex in structure and high in machining difficulty.

(4) Because the required structure and size of the groove to be repaired are complex, the machined area needs to be polished in order to eliminate the non-smooth or partially non-satisfactory structures such as machined edges and corners, sharp corners and the like; meanwhile, in order to avoid welding defects such as slag inclusion, unfused welding and the like of repair welding seams, each layer or each repair welding seam needs to be locally ground in the repair welding process. It is therefore necessary to develop a specific depth setting tool that is flexible to operate, has a depth that is accessible, and is customizable for the sanding head.

In order to overcome the technical difficulties, a local processing and removing method for the defects of the hyperboloid depth weld joint needs to be developed on the basis of the existing processing resources of companies so as to ensure that the defects of the hyperboloid depth weld joint can be successfully found and completely removed, and meanwhile, the defect removing area is processed into a groove to be repaired and welded, which meets the requirement of repair welding operation.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a local processing and removing method for the defects of the hyperboloid depth weld.

The method mainly solves the problem of partial machining and clearing of the hyperboloid depth welding defects, successfully finds out the welding line defects in the machining process and completely clears the welding line defects, and finally processes the welding line defects to form the groove to be repaired, which meets the requirement of repair welding operation, so as to ensure that the hyperboloid depth welding line defects are repaired once to be qualified.

In order to solve the technical problems, the technical scheme of the invention is as follows: a local processing and removing method for defects of a hyperboloid depth weld joint comprises the following steps:

step 1: marking the weld defect position of a workpiece, and marking transverse and circumferential central lines of a groove to be repaired welded and surface machining boundary reference lines on the outer surface of the workpiece, wherein the groove to be repaired welded is a U-shaped deep groove;

step 2: clamping and aligning a workpiece;

step 3: adopting a gang drill method to process the arc-shaped groove, wherein the arc length and width of the arc-shaped groove are the same as the arc length and width of the bottom of the groove to be repaired and welded, the arc length and width of the bottom of the groove to be repaired and welded are larger than the arc length and width of the weld defect, and the processing depth of the arc-shaped groove is 8-10 mm above the depth position of the weld defect;

step 4: milling two side slopes of the arc-shaped groove, removing the left sharp angle, and grinding the bottom of the arc-shaped groove 7;

step 5: layering processing in the depth direction, layering visual inspection and liquid permeation inspection are adopted to detect the bottom defect display condition of the arc-shaped groove until the weld defects are cleared, and the arc-shaped groove is processed into a groove to be repaired;

step 6: machining the gradient of steps at two ends of a groove to be repair welded;

step 7: grinding each surface of the groove to be repaired and carrying out visual and liquid penetration inspection on each surface of the groove to be repaired;

step 8: and performing repair welding and nondestructive testing on the groove to be repaired.

Preferably, the step 1 specifically includes: the bottom arc length of the groove to be repaired welded is the weld defect arc length plus the repair welding operation distance of 15-25 mm at each of the two ends, the bottom width is the double-pass welding operation distance, and the gradients of the two ends and the two sides of the groove to be repaired welded are respectively 10-15 degrees; and the transverse and circumferential central lines and the surface machining boundary reference lines of the groove 6 to be repaired are determined according to the bottom arc length and width of the groove to be repaired and the slopes of the two ends and the two sides.

Preferably, the bottom arc length of the groove to be repaired is the weld defect arc length plus the repair welding operation distance of 20mm at each of the two ends, and the gradients of the two ends and the two sides of the groove to be repaired are 12 degrees respectively.

Preferably, the step 2 specifically includes: workpiece clamping alignment and rotation of machine tool coordinate axes are utilized to enable the centers of a machine tool spindle and a valve filler neck assembly of the workpiece to coincide.

Preferably, the step 3 specifically includes: and (3) clamping a phi 16mm standard high-speed steel twist drill bit by adopting a boring and milling composite machine, and drilling arc-shaped grooves at two ends by adopting a gang drill method according to the transverse central line of the groove to be repaired and the interval smaller than 3/4 of the diameter of the drill bit along the circumferential central line until the bottom arc length of the arc-shaped grooves meets the bottom arc length dimension specification of the groove to be repaired.

Preferably, the step 4 specifically includes: milling the bottom of the arc-shaped groove by adopting a boring and milling compound machine to clamp a phi 42mm stepped twist drill, sequentially finishing the machining of gradients of two side surfaces of the arc-shaped groove and a left sharp corner of a phi 16mm standard high-speed steel twist drill, and then clamping a lengthened hard alloy by adopting an electric straight grinder to rotationally file and grind the bottom of the arc-shaped groove and visually inspect and PT the bottom.

Preferably, the step 5 specifically includes: on the basis of always keeping the arc length of the bottom of the arc-shaped groove, repeating the steps 3 and 4 according to the processing amount of 1mm in the depth direction until the weld defect is found by visual inspection or PT; and then, on the basis of the arc length of the bottom of the arc-shaped groove all the time, repeating the sequence number steps 3 and 4 in layers according to the processing amount of 2mm in the depth direction of each time until visual inspection and PT confirm that the weld defects are removed, and processing the arc-shaped groove into the groove to be repaired.

Preferably, the step 6 specifically includes: machining step slopes of two end faces along the circumferential center line of a groove to be repaired welded according to the step ratio of tan beta by adopting a boring and milling composite machine to clamp a phi 16mm standard high-speed steel twist drill bit, and then milling the step slopes of two end faces into slopes by adopting a boring and milling composite machine to clamp a phi 42mm step twist drill bit; the calculation formula of the ladder is as follows: when the gradients of the two ends of the groove to be repaired and welded are beta, the step ratio is equal to tan beta.

Preferably, the step 7 specifically includes: and (3) clamping and lengthening the hard alloy rotary file by adopting an electric straight grinder, and locally polishing the surface of the groove 6 to be repaired and welded so as to meet the shape and size requirements of the groove to be repaired and welded.

Preferably, the step 8 specifically includes: and performing repair welding on the groove to be repaired, and performing nondestructive inspection on the welded joint which is completed by repair welding according to the original welded joint requirement, thereby finishing repair of the hyperboloid depth weld joint defect of the valve filler neck assembly and the spherical seal head of the workpiece.

Compared with the prior art, the invention has the advantages that:

(1) The invention discloses a method for locally processing and clearing defects of a hyperboloid depth weld, which comprises the steps of firstly marking transverse and circumferential central lines and surface processing boundary reference lines of a groove to be repaired and welded on the outer surface of a workpiece through the positions of the defects of the weld, then clamping and aligning the workpiece, firstly processing an arc-shaped groove by adopting a gang drill method, then milling the slopes of two sides of the arc-shaped groove, removing the left sharp corners of a twist drill, grinding the bottom of the arc-shaped groove, and then checking the defect display condition of the bottom of the arc-shaped groove by adopting layering processing and layering visual or PT in the depth direction until the bottom is cleared, processing the arc-shaped groove into the groove to be repaired and welded, processing the stepped slopes of the two ends of the groove to be repaired and welded, and finally grinding each surface of the groove to be repaired and welded to finish the local processing clearing of the defects of the weld;

(2) The boring and milling composite machine provided by the invention is used for clamping a phi 16mm standard high-speed steel twist drill bit, and the machining of the hyperboloid arc-shaped groove can be realized by adopting a gang drill method; according to the boring and milling composite machine, the milling method is adopted to finish the processing of slopes of two side surfaces of the arc-shaped groove and the left sharp angle of the twist drill;

(3) The invention carries out layered processing in the depth direction and cooperates with layered visual inspection and liquid permeation inspection to detect the defect display condition at the bottom of the arc-shaped groove, so that the weld defect can be successfully found and cleaned, the defect can be completely cleaned at one time, and the cleaning efficiency is improved;

(4) The groove which is processed is an arc groove, the groove after defect removal is the groove to be repaired, the arc groove is processed by adopting a gang drill method, the arc length and the width of the arc groove are the same as those of the bottom of the groove to be repaired, the processing depth of the arc groove is 8-10 mm above the depth position of the weld defect, and then layered processing and layered visual processing in the depth direction are adopted, so that the integrity of weld defect removal can be greatly improved by performing fine adjustment according to the actual position of the weld defect while removing the weld defect;

(5) The invention adopts the phi 16mm standard high-speed steel twist drill step gang drill method for the two end surfaces of the arc-shaped groove, so that the efficiency of milling the slopes at the two ends of the groove of the step twist drill can be improved; the lengthened hard alloy rotary file customized by clamping of the electric straight grinder can meet the grinding requirements of each surface of the hyperboloid groove to be welded and in the repair welding process.

Drawings

FIG. 1 is a flow chart of a method for localized process removal of hyperboloid depth weld defects in accordance with the present invention;

FIG. 2 is a schematic view of the structure of the workpiece of the present invention;

FIG. 3 is a schematic diagram of a front cross-sectional structure of a groove to be repaired and welded according to the present invention;

fig. 4 is a schematic top view partial structure of a groove to be repair welded according to the present invention.

Reference numerals illustrate:

1. the valve comprises a spherical seal head, a valve filler neck assembly, a welding seam of the spherical seal head, a stainless steel surfacing layer on the inner wall, a welding seam defect, a groove to be repaired and a groove to be repaired, wherein the spherical seal head is provided with the spherical seal head, the valve filler neck assembly, the spherical seal head and the welding seam, the stainless steel surfacing layer on the inner wall, the spherical seal head is provided with the spherical seal head.

1-1 spherical head boundary, 2-1 valve filler neck assembly boundary;

6-1, a circumferential center line of a groove to be repaired and welded, 6-2, a transverse center line of the groove to be repaired and welded, 6-3 and a surface machining boundary reference line.

Detailed Description

The following describes specific embodiments of the present invention with reference to examples:

it should be noted that the structures, proportions, sizes and the like illustrated in the present specification are used for being understood and read by those skilled in the art in combination with the disclosure of the present invention, and are not intended to limit the applicable limitations of the present invention, and any structural modifications, proportional changes or size adjustments should still fall within the scope of the disclosure of the present invention without affecting the efficacy and achievement of the present invention.

The boring and milling composite machine tool is used as composite machining equipment suitable for milling, drilling, tapping and the like of the end face and the side face of a workpiece, and has the advantages of high machining precision, high machining efficiency, simplicity in workpiece clamping, wide applicability and the like; the portable electric straight grinding machine is used as a manual grinding tool, has the advantages of flexible operation, excellent processing accessibility, customized grinding head according to requirements and the like, and therefore, the combined method of gang drill of a boring and milling combined machine and grinding of the portable electric straight grinding machine is selected to locally remove the defects of the hyperboloid depth weld.

Example 1

As shown in fig. 1, the invention discloses a local processing and removing method for defects of a hyperboloid depth weld, which comprises the following steps:

step 1: marking the position of a weld defect 5 of a workpiece, and marking a transverse center line and a circumferential center line of a groove 6 to be repaired welded and a surface machining boundary reference line on the outer surface of the workpiece, wherein the groove 6 to be repaired welded is a U-shaped deep groove;

step 2: clamping and aligning a workpiece;

step 3: adopting a gang drill method to process the arc-shaped groove 7, wherein the arc length and width of the arc-shaped groove 7 are the same as those of the bottom of the groove 6 to be repaired, and the bottom of the groove 6 to be repaired is longer than those of the weld defect 5, and the processing depth of the arc-shaped groove 7 is 8-10 mm above the depth position of the weld defect 5;

step 4: milling two side slopes of the arc-shaped groove 7, removing the left sharp corners, and grinding the bottom of the arc-shaped groove 7;

step 5: the bottom defect display condition of the arc-shaped groove 7 is checked by adopting layering processing and layering visual and liquid permeation in the depth direction until the weld defect 5 is cleared, and the arc-shaped groove 7 is processed into a groove 6 to be repaired;

step 6: machining the gradient of steps at two ends of the groove 6 to be repaired and welded;

step 7: grinding each surface of the groove 6 to be repaired and carrying out visual and liquid penetration inspection on each surface of the groove 6 to be repaired;

step 8: and carrying out repair welding and nondestructive inspection on the groove 6 to be repaired.

Example 2

As shown in fig. 4, preferably, the step 1 specifically includes: the bottom arc length of the groove 6 to be repaired is the 5 arc length of the weld defect plus the repair welding operation distance of 15-25 mm at each end, the bottom width is the operation distance of double-pass welding, and the gradients at each end and at each side of the groove 6 to be repaired are respectively 10-15 degrees; and the transverse and circumferential central lines and the surface machining boundary reference lines of the groove 6 to be repaired are determined according to the bottom arc length and width of the groove 6 to be repaired and the slopes of the two ends and the two sides.

Preferably, the arc length of the bottom of the groove 6 to be repaired is 5 arc length of the weld defect plus the repair welding operation distance of 20mm at each of the two ends, and the gradients of the two ends and the two sides of the groove 6 to be repaired are 12 degrees respectively.

And the arc length of the surface of the weld defect 5 after the removal is comprehensively determined according to the root arc length, the bottom fillet, the slopes of the two end surfaces and the diameter of the center circle of the weld defect 5 after the removal of the defect.

As shown in fig. 2 and 3, the pressure vessel workpiece comprises a spherical end socket, a valve filler neck assembly 2, a welding seam 3 of the valve filler neck assembly and the spherical end socket, and a stainless steel surfacing layer 4 on the inner wall, wherein the welding seam defect 5 is a defect in a welding seam formed when the valve filler neck assembly 2 is welded with the spherical end socket 1.

Example 3

Preferably, the step 2 specifically includes: workpiece clamping alignment and rotation of machine tool coordinate axes are utilized to enable the centers of a machine tool spindle and a valve filler neck assembly 2 of the workpiece to coincide.

Preferably, the step 3 specifically includes: and (3) clamping a phi 16mm standard high-speed steel twist drill bit by adopting a boring and milling composite machine, and drilling arc-shaped grooves 7 at two ends by adopting a gang drill method according to the transverse central line and the circumferential central line of the groove 6 to be repaired and the spacing smaller than 3/4 of the diameter of the drill bit until the bottom arc length of the arc-shaped grooves 7 meets the specification of the arc length of the bottom of the groove 6 to be repaired.

Example 4

Preferably, the step 4 specifically includes: milling the bottom of the arc-shaped groove 7 by adopting a boring and milling compound machine to clamp a phi 42mm stepped twist drill bit, sequentially finishing the machining of gradients of two sides of the arc-shaped groove 7 and a left sharp corner of a phi 16mm standard high-speed steel twist drill bit, and then clamping a lengthened hard alloy by adopting an electric straight mill to clamp, rotationally filing and grinding the bottom of the arc-shaped groove 7, and carrying out visual inspection and PT on the bottom.

Preferably, the step 5 specifically includes: on the basis of always keeping the arc length at the bottom of the arc-shaped groove 7, repeating the steps 3 and 4 in layers according to the processing amount of 1mm in the depth direction until the weld defect 5 is found by visual inspection or PT; and then, on the basis of the arc length at the bottom of the arc-shaped groove 7 all the time, repeating the sequence number steps 3 and 4 in layers according to the processing amount of 2mm in the depth direction of each time until the weld defect 5 is completely cleared by visual inspection and PT confirmation, and processing the arc-shaped groove 7 into the groove 6 to be repaired.

Example 5

Preferably, the step 6 specifically includes: machining the ladder slopes of the two end faces along the circumferential center line of the groove 6 to be repaired and welded according to the ladder ratio of tan beta by adopting a boring and milling composite machine to clamp a phi 16mm standard high-speed steel twist drill bit, and then milling the ladder slopes of the two end faces into slopes by adopting a boring and milling composite machine to clamp a phi 42mm ladder twist drill bit; the calculation formula of the ladder is as follows: when the gradients of the two ends of the groove 6 to be repaired and welded are beta, the step ratio is equal to tan beta.

Preferably, the step 7 specifically includes: and (3) clamping and lengthening the hard alloy rotary file by adopting an electric straight grinder, and locally polishing the surface of the groove 6 to be repaired and welded so as to meet the shape and size requirements of the groove 6 to be repaired and welded.

Preferably, the step 8 specifically includes: and repairing the groove 6 to be repaired and carrying out nondestructive inspection on the welded seam which is completed by repairing according to the original welded seam requirement, thereby finishing repairing of the hyperboloid depth welded seam defect of the valve filler neck assembly and the spherical sealing head of the workpiece.

Example 6

(1) As shown in fig. 3, marking the position of a weld defect 5 of a workpiece, and marking a transverse central line and a circumferential central line of a groove 6 to be repaired and a surface machining boundary reference line; the depth of the weld defect 5 is 85.3mm;

as shown in fig. 4, a circumferential center line 6-1 of a groove to be repair welded, a transverse center line 6-2 of the groove to be repair welded and a surface machining boundary reference line 6-3 are marked at the position of the surface of the workpiece corresponding to the weld defect 5, wherein the spherical head boundary 1-1 is a boundary of one side of the spherical head 1, which is close to the valve filler neck assembly 2, and the valve filler neck assembly boundary 2-1 is a boundary of one side of the valve filler neck assembly 2, which is close to the spherical head 1;

(2) Workpiece clamping alignment and rotation of a machine tool coordinate axis are utilized to enable the center of a machine tool spindle and the center of the valve filler neck assembly 2 to coincide;

(3) Clamping a phi 16mm standard high-speed steel twist drill bit by adopting a boring and milling composite machine, and drilling 76mm deep holes at two ends by adopting a gang drill method according to the interval smaller than 12mm (3/4 of the diameter of the drill bit) along the transverse central line and the circumferential central line of the groove 6 to be repaired and welded until the arc length at the bottom of the arc-shaped groove 7 meets the specified size;

as shown in fig. 4, the arc length of the weld defect is smaller than the arc length at the bottom of the arc-shaped groove 7, the width of the weld defect is smaller than the width at the bottom of the arc-shaped groove 7, the arc length at the root after defect removal is the arc length at the bottom of the arc-shaped groove 7, and the arc length of the defect removal surface is the arc length of the groove 6 to be repaired;

(4) Milling a 76mm hole bottom by adopting a boring and milling composite machine to clamp a phi 42mm stepped twist drill, and finishing the machining of gradients of two side surfaces of the arc-shaped groove 7 and a left sharp corner of the twist drill at one time so as to facilitate visual inspection and PT of the bottom of the arc-shaped groove 7;

the bottom of the arc-shaped groove 7 is rotationally filed and ground by adopting a lengthened hard alloy rotary file customized by the clamping of a portable electric direct grinding machine, visual inspection and PT are carried out on the bottom, and defect display conditions are observed;

(5) The serial numbers (3) and (4) are repeated in layers according to the processing amount of 1mm in the depth direction (the arc length of the bottom of the arc-shaped groove 7 is always kept) until the defects are found by visual inspection or PT; then, layering and repeating serial numbers (3) and (4) according to the processing amount of 2mm in each depth direction (the arc length at the bottom of the arc-shaped groove 7 is always kept) until visual inspection and PT confirm that the weld defects 5 are completely removed, processing the arc-shaped groove 7 into a groove 6 to be repaired, and as shown in fig. 4, removing the arc length of the surface of the defect, namely, the arc length of the groove 6 to be repaired;

(6) Machining the gradient of the steps at the two ends of the standard high-speed steel twist drill with the diameter of 16mm by adopting a boring and milling composite machine, and then milling the gradient of the steps at the two ends of the standard high-speed steel twist drill with the diameter of 42mm by adopting the boring and milling composite machine to form a slope according to the steps with the diameter of 1X 5mm along the circumferential center line of the groove;

the step calculation method comprises the following steps: the gradient of the two ends of the groove 6 to be repair welded is beta, the step ratio is approximately equal to tan (beta), when beta=12°, the step ratio is tan (12 °), for this reason, a 1×5mm step is selected, and at this time, the machining efficiency is relatively high and pits are not formed.

(7) The surface of the groove 6 to be repaired is locally ground by adopting a lengthened hard alloy rotary file customized by clamping of a portable electric straight grinding machine so as to meet the shape and size requirements of the groove 6 to be repaired;

(8) And repairing welding is carried out on the groove 6 to be repaired according to the repairing welding process requirement, nondestructive inspection is carried out on the welded seam which is completed by repairing welding according to the original welded seam requirement, and the result is inspected to be qualified once, so that the repair of the hyperboloid depth welded seam defects of the valve filler neck assembly 2 and the spherical head 1 of the workpiece is completed satisfactorily.

The comparison of the prior art method with the method according to the invention is shown in Table 1:

table 1 comparison of the existing process with the process of the present invention

The defects of the hyperboloid weld joint are removed by adopting a conventional polishing method, so that arc grooves cannot be formed, excessive damage to a base metal is easy to cause, the efficiency is low, and particularly when the defects are deep, the repair weld joint is seriously deviated from an original weld joint area to influence the in-service inspection of the equipment weld joint; although the air carbon arc gouging can remove the defects of the hyperboloid depth weld, the method can cause carburization of the surface of the groove to be repaired, so that the weldability of the material is reduced and the material is forbidden to use.

The method solves the problem of local processing and cleaning of the hyperboloid depth weld defects, and finally forms the arc-shaped groove to be repaired and welded which is beneficial to subsequent repair and welding; the fact proves that the invention not only successfully finds out the hyperboloid depth weld defects of the valve filler neck assembly 2 and the spherical head 1 and smoothly eliminates the defects, but also forms the arc-shaped groove to be repaired to facilitate repair welding operation, and finally, the repair welding is qualified once.

The working principle of the invention is as follows:

as shown in figures 1-4, the invention discloses a local processing and clearing method for a hyperboloid depth weld defect, which comprises the steps of firstly scribing a transverse central line, a circumferential central line and a surface processing boundary reference line of a groove to be repaired and on the outer surface of a workpiece through the position of the weld defect, then clamping and aligning the workpiece, firstly processing an arc groove by adopting a gang drill method, then milling the slopes of two side surfaces of the arc groove, removing the left sharp corners of a twist drill, grinding the bottom of the arc groove, carrying out inspection and defect display on the bottom of the arc groove by adopting layering processing and layering visual or PT in the depth direction until clearing, processing the arc groove into a groove to be repaired, then processing the stepped slopes of two ends of the groove to be repaired, and finally grinding each surface of the groove to be repaired to finish the local processing and clearing of the weld defect.

The pressure vessel industry usually adopts an air carbon arc gouging and/or polishing method to remove the weld defects locally, and for removing the weld defects locally with hyperboloid depth, the conventional polishing method cannot form an arc groove to cause excessive damage to the base metal and has low efficiency; when the carbon arc gouging is adopted, the surface carburization of the groove to be repaired is caused, and during subsequent repair welding, cold cracks are extremely easy to generate, so that the weld joint repair is disqualified. Therefore, the invention develops a local processing and removing method for the hyperboloid depth weld defects, which not only avoids excessive damage to the base metal and the surface carburization of the groove to be repaired and has relatively high efficiency, but also successfully finds the weld defects to completely remove, and the shape and the size of the formed groove to be repaired meet the requirement of repair welding operation, so that the weld defects are ensured to be repaired to be qualified once.

The boring and milling composite machine provided by the invention is used for clamping a phi 16mm standard high-speed steel twist drill bit, and the machining of the hyperboloid arc-shaped groove can be realized by adopting a gang drill method; according to the boring and milling composite machine tool, the milling method is adopted to finish machining of slopes of two side surfaces of the arc-shaped groove and a sharp corner left by the twist drill.

The invention can successfully find out and clean the weld defects, ensure that the defects are completely cleaned at one time and improve the cleaning efficiency by carrying out layered processing in the depth direction and matching with layered visual inspection and liquid penetration inspection on the display condition of the defects at the bottom of the arc-shaped groove.

The groove which is processed is an arc groove, the groove after defect removal is the groove to be repaired, the arc groove is processed by adopting a gang drill method, the arc length and the width of the arc groove are the same as those of the bottom of the groove to be repaired, the processing depth of the arc groove is 8-10 mm above the depth position of the weld defect, and then layering processing and layering visual processing in the depth direction are adopted, so that the integrity of weld defect removal can be greatly improved by performing fine adjustment according to the actual position of the weld defect while removing the weld defect.

The invention adopts the phi 16mm standard high-speed steel twist drill step gang drill method for the two end surfaces of the arc-shaped groove, so that the efficiency of milling the slopes at the two ends of the groove of the step twist drill can be improved; the lengthened hard alloy rotary file customized by clamping of the electric straight grinder can meet the grinding requirements of each surface of the hyperboloid groove to be welded and in the repair welding process.

While the preferred embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various changes may be made without departing from the spirit of the present invention within the knowledge of those skilled in the art.

Many other changes and modifications may be made without departing from the spirit and scope of the invention. It is to be understood that the invention is not to be limited to the specific embodiments, but only by the scope of the appended claims.

Claims (10)

1. The local processing and removing method for the hyperboloid depth weld defects is characterized by comprising the following steps of:

step 1: marking the position of a weld defect (5) of a workpiece, and marking a transverse center line and a circumferential center line of a groove (6) to be repaired welded and a surface machining boundary reference line on the outer surface of the workpiece, wherein the groove (6) to be repaired is a U-shaped deep groove;

step 2: clamping and aligning a workpiece;

step 3: adopting a gang drill method to process an arc-shaped groove (7), wherein the arc length and width of the arc-shaped groove (7) are the same as the arc length and width of the bottom of the groove (6) to be repaired, the arc length and width of the bottom of the groove (6) to be repaired are larger than those of the weld defect (5), and the processing depth of the arc-shaped groove (7) is 8-10 mm above the depth position of the weld defect (5);

step 4: milling two side slopes of the arc-shaped groove (7) and removing the left sharp angle, and grinding the bottom of the arc-shaped groove (7);

step 5: layering processing and layering visual inspection in the depth direction and liquid permeation inspection are adopted to detect the bottom defect display condition of the arc-shaped groove (7) until the weld defect (5) is cleared, and the arc-shaped groove (7) is processed into a groove (6) to be repaired;

step 6: machining the gradient of steps at two ends of a groove (6) to be repaired;

step 7: grinding each surface of the groove (6) to be repaired and carrying out visual and liquid permeation inspection on each surface of the groove (6) to be repaired;

step 8: and (5) carrying out repair welding and nondestructive inspection on the groove (6) to be repaired.

2. The method for removing defects in a hyperboloid depth weld according to claim 1, wherein the step 1 specifically comprises: the arc length of the bottom of the groove (6) to be repaired is the arc length of the weld defect (5) plus the repair welding operation distance of 15-25 mm at each end, the width of the bottom is the operation distance of double-pass welding, and the gradients of the two ends and the two sides of the groove (6) to be repaired are 10-15 degrees respectively; and the transverse and circumferential central lines and the surface machining boundary reference line of the groove (6) to be repaired are determined according to the bottom arc length and width of the groove (6) to be repaired and the slopes of the two ends and the two sides.

3. The method for removing defects in a hyperboloid depth weld according to claim 2, wherein: the arc length of the bottom of the groove (6) to be repaired is the arc length of the weld defect (5) plus the repair welding operation distance of 20mm at each of the two ends, and the gradients of the two ends and the two sides of the groove (6) to be repaired are 12 degrees respectively.

4. The method for removing defects in a hyperboloid depth weld according to claim 1, wherein the step 2 specifically comprises: workpiece clamping alignment and rotation of machine tool coordinate axes are utilized to enable the centers of a machine tool spindle and a valve filler neck assembly (2) of the workpiece to coincide.

5. The method for removing defects in a hyperboloid depth weld according to claim 1, wherein the step 3 is specifically: and (3) clamping a phi 16mm standard high-speed steel twist drill bit by adopting a boring and milling composite machine, and drilling arc-shaped grooves (7) at two ends by adopting a gang drill method according to the transverse central line of the groove (6) to be repaired welded and the interval smaller than 3/4 of the diameter of the drill bit along the circumferential central line until the bottom arc length of the arc-shaped grooves (7) meets the specification of the arc length at the bottom of the groove (6) to be repaired welded.

6. The method for removing defects in a hyperboloid-depth weld according to claim 5, wherein the step 4 is specifically: milling the bottom of an arc-shaped groove (7) by adopting a boring and milling compound machine to clamp a phi 42mm stepped twist drill, sequentially finishing the machining of gradients of two sides of the arc-shaped groove (7) and a left sharp corner of a phi 16mm standard high-speed steel twist drill, and then clamping a lengthened hard alloy rotary file by adopting an electric straight grinder to grind the bottom of the arc-shaped groove (7) and visually checking and PT.

7. The method for removing defects in a hyperboloid depth weld according to claim 1, wherein the step 5 is specifically: on the basis of always keeping the arc length of the bottom of the arc-shaped groove (7), repeating the steps 3 and 4 in layers according to the processing amount of 1mm in the depth direction until the weld defect (5) is found by visual inspection or PT; and then, on the basis of the arc length of the bottom of the arc-shaped groove (7) all the time, layering and repeating the sequence number steps 3 and 4 according to the processing amount of 2mm in each depth direction until visual inspection and PT confirm that the weld defect (5) is completely cleared, and processing the arc-shaped groove (7) into a groove (6) to be repaired.

8. The method for removing defects in a hyperboloid-depth weld according to claim 1, wherein the step 6 is specifically: clamping a phi 16mm standard high-speed steel twist drill bit by adopting a boring and milling composite machine, machining the step gradients of two end faces along the circumferential center line of a groove (6) to be repaired and welded according to the step ratio of tan (beta), and then clamping the phi 42mm step twist drill bit by adopting the boring and milling composite machine, wherein the step gradients of the two end faces are slope surfaces; the calculation formula of the ladder is as follows: when the gradients at the two ends of the groove (6) to be repaired and welded are beta, the step ratio is equal to tan (beta).

9. The method for removing defects in a hyperboloid depth weld according to claim 1, wherein the step 7 is specifically: and (3) clamping and lengthening the hard alloy rotary file by adopting an electric straight grinder, and locally polishing the surface of the groove (6) to be repaired and welded so as to meet the shape and size requirements of the groove (6) to be repaired and welded.

10. The method for removing defects in a hyperboloid-depth weld according to claim 1, wherein the step 8 is specifically: and (3) repairing welding is carried out on the groove (6) to be repaired, and nondestructive inspection is carried out on the welded seam which is completed by repairing welding according to the original welded seam requirement, so that the repair of the hyperboloid depth welded seam defect of the valve filler neck assembly and the spherical sealing head of the workpiece is completed.