JP2011161501A - Test specimen for skill evaluation and skill evaluation method for substitutional end tab working procedure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a test specimen for skill evaluation of substitutional end tab working procedure, which can economically and efficiently examine a portion where weld defect tends to be caused or a portion where strength is required. <P>SOLUTION: The test specimen for skill evaluation (1) includes a first and a second steel plates (2, 3), which are connected using a backing plate (8). On edge faces vertical to welding groove (9), that is, on the first side edge face (11), two pairs of steps (14a to 14d) are arranged so that the closest portions (16, 16) to the welding groove (9) become externally projected in relation to surrounding parts (15a, 15b). In this way, the first and second reference faces (15a, 15b) are formed. On the second side edge face (12), two pairs of steps (20a to 20d) are installed similarly, and then a third and a fourth reference faces (19a, 19b) are formed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a so-called alternative end tab method in which a ceramic end plate is brought into contact with each of the start end and the end end of welding and welding, and a test piece for evaluating the welding skill, and a skill evaluation method It is about.

  Structures made of steel are used for constructions that require strength, such as bridges and buildings, and such structures are called steel structures. The steel structure is composed of a plurality of steel materials, and the steel materials are connected to each other by welding. The steel material to be welded is called a base material. For example, when a base material composed of two steel plates is joined by welding, the weld surfaces of the base materials are abutted at a predetermined interval. A welding groove is formed from the pair of welded surfaces that are abutted against each other, but the welded surface is shaved in advance as necessary to form a desired groove suitable for welding. Apply backing metal to the back of the two base materials and fuse them to the base material. This is to prevent the weld metal from dripping from the welding groove during welding. Next, an auxiliary plate made of steel, that is, an end tab is fused to the end face of the side of the base material so as to extend the welding groove. By so-called arc welding, a welding metal is poured into the welding groove so that the base metal and the welding metal are integrated. The end tab can be left as it is after welding, but it is usually cut because this portion becomes a portion protruding from the base material and stress is easily concentrated. The purpose of providing such an end tab at the time of welding includes preventing the weld metal from sagging. Another object is to extend the welding start position and end position where welding defects are likely to occur so that the welding defects are less likely to occur in the welded portion of the base material. Such a method of welding using an end tab is called an end tab method.

  The end tab method is excellent because it can be appropriately welded even with a thick steel plate. However, labor is required because the end tab must be particularly fused before welding or the end tab must be cut after welding. Such ceramic end tabs that do not need to be fused or cut, that is, alternative end tabs are also well known. The method of welding using the alternative end tab is called the alternative end tab method and is carried out as follows. Similar to the end tab method, the two base materials are butted at a predetermined interval on the welding surface, and a backing metal is attached. Close both ends of the welding groove with alternative end tabs. In other words, the pair of alternative end tabs are brought into contact with both side ends of the two base materials, thereby closing the boundary between the two base materials. In this state, the alternative end tab is firmly fixed with a wire for clamping. Arc welding. After welding, the alternative end tab can be removed by tapping it. The alternative end tab method is highly efficient because it requires few steps and is widely used.

  High skill is required for welding. When constructing a steel structure, the operator is required to have a predetermined skill, so various tests are performed as appropriate. Although the name of the test is not specifically mentioned, there is also an advanced test that checks for the presence of very advanced skills. Such advanced verification can be applied to, for example, large-scale work that requires welding of large steel materials with a steel plate thickness exceeding 40 mm. ing. The examinee welds the specimen. Thereafter, the test piece is cut into strips, and bending tests are performed from various directions. In this way, the presence or absence of welding defects is strictly tested. This is to evaluate whether or not it has the necessary skills even for large-scale construction that requires extremely high skills. However, such an inspection is expensive. In the case of a general steel structure, the thickness of the base material is a thin steel material such as 6 mm, 9 mm, or 10 to 40 mm, and it can be welded relatively easily if it has a certain level of skill. Therefore, such a highly difficult test for checking the presence or absence of a very advanced skill is not necessarily essential for a worker who constructs a general steel structure. However, there is a need to objectively evaluate whether such workers have the necessary skills. If the test is made simpler, there will be more opportunities to evaluate skills, and the test will become widespread and will contribute to the reliability of general steel structures.

  For example, an AW test is well known as such a test. There are various types of AW tests, and test pieces with a plate thickness of 19 mm are used for tests of the alternative end tab method. FIG. 4 shows the test piece 50 as viewed from above. The test piece is composed of two steel plates 51 and 52, and the steel plates 51 and 52 are opposed to each other with their welding surfaces 53 and 54 spaced apart from each other by a predetermined distance. Although not shown in FIG. 4, a backing metal is provided on the back side of the facing portion. A welding groove 55 is formed from the welding surfaces 53 and 54 and the backing metal. Alternative end tabs 57 and 58 are fixed to such a test piece 50. Next, arc welding is performed, and a weld metal is poured into the welding groove.

  The quality of welding is inspected as follows. First, the alternative end tabs 57 and 58 are removed, and the portions are visually confirmed. Next, the welded portion is visually inspected over the entire range 60, and the presence or absence of defects inside the welded portion is examined by X-ray. Thereafter, the test piece 50 is cut at a portion 40 mm inside from the side end face. Furthermore, it cut | disconnects in the part 0.3 mm inside from an edge part. FIG. 4 shows cut surfaces 61 and 62 and cut surfaces 66 and 67 cut in this way. These cut surfaces 61, 62, 66, 67 are mirror-finished, and the weld metal portion is treated with a chemical as required. It is visually inspected whether or not the welded portions of these cut surfaces 61, 62, 66, and 67 are integrated with the base material and whether or not there is a welding defect. That is, macro inspection is performed. The backing metal is also removed, and the slow cutting surface is macro-inspected.

JP-A-6-265529

  Although not directly related to the verification, as described in Patent Document 1, an inspection method for examining the presence or absence of welding defects using ultrasonic waves is well known. In this inspection method, an ultrasonic beam is incident from a steel plate at a predetermined angle, and the ultrasonic beam is applied to the welded portion. Then, the reflected wave is detected to investigate the presence or absence of welding defects. For example, if there is a gap or the like in the welded part, the ultrasonic wave is reflected at that part and the gap is detected. The ultrasonic welding inspection method is excellent in that the inspection can be easily performed because it is not necessary to cut or destroy the test piece.

  By using the test piece 50 as used in the AW certification, the welding skill can be evaluated in detail. And it is relatively easy to evaluate welding skills compared to other very advanced tests. However, there are some problems. Specifically, in order to inspect a portion where welding defects are likely to occur, there is a problem that the shape is not necessarily suitable. Welding defects are likely to occur at the welding start and end positions. That is, it is likely to occur near the alternative end tabs 57 and 58. In FIG. 4, this is the part indicated by reference numeral 64. In the AW test, the test piece 50 is cut at the cutting surfaces 66 and 67 in order to inspect the portion 64. However, it is difficult to cut the test piece 50 with an accurate dimension. That is, in order to cut at the cutting surfaces 66 and 67, 0.3 mm is accurately measured from the end surface, or the cutting surfaces 61 and 62 inside 40 mm from the end surface are first cut and these are used as reference surfaces. There is no choice but to cut at 97mm. Then, since the reference plane is not particularly provided on the test piece 50 itself, it is difficult to slice the test piece 50 with a thickness of 0.3 mm from the end. Moreover, it cannot be guaranteed whether or not it can be cut parallel to the end face. Furthermore, since the cut surfaces 66 and 67 extend over the entire length in the longitudinal direction of the test piece 50, if only the welded portion is to be mirror-finished, the portion becomes concave and difficult to polish. There is also. From the above viewpoint, the test piece 50 is not necessarily a shape suitable for inspecting the portion indicated by the reference numeral 64 in the vicinity of the end face.

  There is also a problem with the cost of the certification. Regarding costs, there are costs for the inspection itself, procedures related to the examination, and administrative costs. As the former cost, for example, in the AW test, since the test piece 50 must be cut in a predetermined cross section, it is expensive. In addition, since ultrasonic inspection is cheaper than X-ray inspection, we want to devise a combination of ultrasonic inspection. Ultrasonic inspection is more suitable for surface conditions such as poor penetration at the edges. There is also an advantage that defects can be inspected in more detail. To explain the cost of the latter, in the conventional examination, the examination venue is designated to ensure the fairness of the examination, and the students are tested all at once. If this is the case, the test venue must be specially provided, which increases the operating costs, and the examinee increases the transportation costs. If we consider taking a method that does not provide a test site, we can save the operational costs associated with the certification. Specifically, a test piece is sent to each examinee, and after the examinee performs welding, the test piece is returned and verified. When this method is adopted, it is required that the test results remain as evidence when the returned specimen is tested. Specifically, for example, when a test piece is cut and inspected, it is required that the cut with a specified accurate dimension remains as evidence in the cut test piece. This is to ensure the fairness or objectivity of the test. However, in the test piece 50 described above, such evidence does not remain in the fragment after being cut. The test piece 50 is engraved with markings K ′ and K ′. However, when the test piece 50 is cut at the cut surfaces 61, 62, 66 and 67, the test piece with the engraving K ′ and K ′ has an end face. This is because it cannot be determined whether or not the cutting has been performed accurately at 0.3 mm. In that case, the test cannot be performed without specially preparing a test venue or without monitoring by a member of a third-party organization, and the cost of the test increases.

  An object of the present invention is to provide a test piece for evaluating the skill of an alternative end tab method and a method for evaluating the skill, which have solved the conventional problems as described above. Specifically, it is possible to efficiently inspect parts that are prone to welding defects, the test results remain as evidence on the test piece, and therefore an alternative that can evaluate skills inexpensively and objectively It aims at providing the test piece for skill evaluation in an end tab construction method, and the skill evaluation method.

  In order to achieve the above object, the present invention comprises a pair of steel plates connected to each other by a backing metal. The pair of steel plates are arranged with a gap so that the respective welding surfaces face each other, thereby forming a welding groove that is filled by welding. At least a pair of steps is formed on the end face of the test piece, which is perpendicular to the welding groove. As a result, the vicinity of the welding groove protrudes outward by a predetermined amount compared to the surrounding area. Such a step is formed to be 0.3 to 1.5 mm.

Thus, the invention according to claim 1 is composed of a pair of steel plates connected by a backing metal, and the pair of steel plates is arranged with a gap so that the respective welding surfaces face each other, thereby A welding groove to be filled by welding is formed, and at least a pair of steps are formed on an end surface perpendicular to the welding groove, so that the vicinity of the welding groove is compared with the surrounding area. It is configured to protrude outward only by a fixed amount.
According to a second aspect of the present invention, in the test piece according to the first aspect, at least a pair of steps are provided on both end faces perpendicular to the welding groove, whereby both end faces of the welding groove are provided. Is configured to protrude outward by a predetermined amount compared to the surroundings.
The invention according to claim 3 is the test piece according to claim 1 or 2, wherein one steel plate of the pair of steel plates is thicker than the other steel plate, and the welding surface of the other steel plate is oblique. The groove is cut, and a groove having a cross-sectional shape is formed in the welding groove.
A fourth aspect of the present invention is the test piece according to any one of the first to third aspects, wherein the step is formed to be 0.3 to 1.5 mm.

The invention according to claim 5 is a method for evaluating the skill of the alternative end tab method by using the test piece according to any one of claims 1 to 4, and is provided at both end faces of the welding groove of the test piece. A pair of ceramic alternative end tabs are brought into contact and welded to the welding groove, and after the alternative end tab is removed, the end face of the test piece is sliced in parallel with the end face at the stepped portion. The skill is evaluated according to the state of the sliced cross section.
A sixth aspect of the present invention is the skill evaluation method according to the fifth aspect, wherein the welded portion is evaluated by an ultrasonic flaw detection method before performing the slicing.

  As described above, according to the present invention, the test piece is formed with at least a pair of steps on the end surface perpendicular to the welding groove so that the vicinity of the welding groove is removed by a predetermined amount compared to the surroundings. Since it protrudes in the direction, the first to third effects can be obtained. First, the first effect is an effect that can easily inspect a portion requiring the most inspection, that is, a welding state in the vicinity of the end portion. That is, since only the vicinity of the welding groove protrudes outward, this portion is easy to cut off. If it does so, only the vicinity of the groove for welding can be shaved with a grinder etc., and the state of welding near the end can be inspected. Even when the test piece is sliced with a cutter or the like, the cutting length may be short. Moreover, since it protrudes outward, it is easy to grind and to carry out mirror surface processing. By these, it can test | inspect cheaply. The second and third effects are due to the reference surface being formed on the end surface of the test piece. According to the present invention, a pair of steps are formed on the end surface perpendicular to the welding groove, and different surfaces are formed in the peripheral portion away from the welding groove and in the vicinity of the welding groove. It will be. The surface of this surrounding part can be used as a reference surface. The reference surface provides the second effect, that is, the effect of accurately measuring the scraping amount in the vicinity of the welding groove. That is, when scraping the vicinity of the welding groove, the scraping amount can be accurately measured by measuring the position from the reference plane. Further, it can be cut accurately in parallel with the reference plane. As a result, it is possible to evaluate the welding state in the vicinity of the end portion at a portion where the amount of scraping is always constant, and the skill can be evaluated fairly and objectively. The third effect is an effect in which evidence of the scraping amount remains on the test piece. That is, even if the vicinity of the welding groove is scraped off, the reference plane remains, so the scraped amount remains as evidence. If it does so, it will become possible to carry out a test, without providing a special test site and performing a test.

  According to another invention, among the pair of steel plates constituting the test piece, one steel plate is thicker than the other steel plate, and the other steel plate is cut obliquely at the welding surface. As a result, a groove having a letter-shaped cross section is formed in the welding groove. Therefore, a groove similar to the groove formed in the base metal is formed, and the required welding skill can be verified in a form that is close to reality. According to another invention, in the test, the welded portion is evaluated by ultrasonic flaw detection before slicing the end face of the test piece. Then, since the flaw detection is performed with the steel material remaining on the end face, the portion to be sliced can be flawed accurately and easily. Thereafter, the vicinity of the end face is sliced and the welded part near the end face is inspected, and the inspection result by ultrasonic flaw detection is evaluated in that part. If it does so, reliability will be ensured also about the test result of the ultrasonic flaw detection in the part which is not cut | disconnected. This makes it possible to inspect for the presence or absence of welding defects in the entire welded part at low cost without cutting the test piece at various parts.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the test piece which concerns on embodiment of this invention, The (a) is a perspective view, The (a) is a top view. It is a top view of a test piece explaining the effect | action of the test piece which concerns on embodiment of this invention. It is a top view which shows a part of test piece explaining the effect | action of the test piece which concerns on embodiment of this invention. It is a top view which shows the conventional test piece.

  Hereinafter, the skill evaluation test piece 1 according to the embodiment of the present invention will be described. The skill evaluation test piece 1 is composed of a first steel plate 2 and a second steel plate 3 as shown in FIG. The first and second steel plates 2 and 3 are steel plates having thicknesses of 16 mm and 22 mm, respectively. A first welding end face 5 is formed on the first steel plate 2, and the first welding end face 5 is cut off obliquely, for example, at an angle of 35 °. The second welding end surface 6 is also formed on the second steel plate 3, but the second welding end surface 6 is a vertical surface. The first and second steel plates 2 and 3 are arranged so that the first and second welding end faces 5 and 6 face each other with a predetermined gap. And the backing metal 8 is temporarily fixed to the back side of the 1st, 2nd steel plates 2 and 3, and the 1st and 2nd steel plates 2 and 3 are connected. The first and second welding end faces 5 and 6 and the backing metal 8 form a welding groove 9 having a letter-shaped groove.

  The skill evaluation test piece 1 according to the present embodiment is characterized by lateral end faces, that is, first and second side end faces 11 and 12. The first and second side end faces 11 and 12 are end faces perpendicular to the welding groove 9. Two pairs of steps are formed on each of the first and second side end faces 11 and 12. That is, first to fourth steps 14 a to 14 d are formed on the first side end face 11. The first step 14a and the fourth step 14d are 0.7 mm steps, which are a pair of steps. The second step 14b and the third step 14c are 0.3 mm steps, which are a pair of steps. By these steps 14a to 14d, first reference surfaces 15a and 15a and second reference surfaces 15b and 15b are formed on the first side end surface 11. Surfaces in the vicinity of the welding groove 9 are first contact surfaces 16 and 16 on which the alternative end tabs are contacted. In the present embodiment, predetermined markings K and K are given to the second reference surfaces 15b and 15b.

  The second side end face 12 is also formed in the same manner as the first side end face 11. That is, fifth to eighth steps 20a to 20d are also formed on the second side end face 12, and thereby, the third reference surfaces 19a and 19a, the fourth reference surfaces 19b and 19b, Abutting surfaces 21 and 21 are formed. The fifth and eighth steps 20a and 20d are 0.7 mm, and the sixth and seventh steps 20b and 20c are 0.3 mm. The fourth reference surfaces 19b and 19b are also marked with K and K, but are not shown in FIG.

  A method for evaluating the welding skill by performing the alternative end tab method using the skill evaluation test piece 1 according to the present embodiment will be described. As shown in FIG. 2, the alternative end tabs 30, 31 are brought into contact with the first and second contact surfaces 16, 21 to close the end of the welding groove 9. The alternative end tabs 30 and 31 are fixed by the clamp wire 33. Arc welding is performed, a weld metal is poured into the welding groove 9, and the first and second steel plates 2 and 3 are welded. In FIG. 2, the welded portion 35 is indicated by hatching. The clamping wire 33 is removed, and the alternative end tabs 30 and 31 are removed. Welding is complete.

Evaluation of welding skill, that is, determination of the quality of welding is performed in the following order.
First, an ultrasonic flaw detection test is performed. FIG. 2 shows a state in which an ultrasonic beam is applied to the vicinity 39 of the welded portion 35 by the ultrasonic transmitter 38. The ultrasonic flaw detection method is a method of detecting flaws and flaws generated inside by analyzing reflected ultrasonic waves as is well known in the art. Since the incident angle of the ultrasonic beam can be set to 65 °, for example, the path of the ultrasonic beam can be made long, and the presence or absence of welding defects in the vicinity of the end portion 39 can be examined in detail. Subsequently, the other end vicinity 40 and the center portion 41 of the welded portion 35 are also subjected to ultrasonic flaw detection. By the way, the welding defects near the end portions 39 and 40 are also inspected in the next macro inspection, and as a result, the accuracy of the ultrasonic flaw detection test is verified. If it does so, the reliability of the ultrasonic flaw detection test implemented in the center part 41 can be ensured.

  Next, a macro inspection is performed. The first side end face 11 is cut thinly. More specifically, the first contact surfaces 16 and 16 and the welded portion 35 are cut in parallel with the second reference surfaces 15b and 15b. Or cut. As shown in FIG. 3, when the cutting surface 43 is cut, the second and third steps 14b and 14c remain slightly. If the remaining height 44 is measured, the cut thickness can be determined. Since the second reference surfaces 15b and 15b are left in the skill evaluation test piece 1, the cut thickness or the cut thickness is clear. In other words, it remains as evidence. The cut surface is polished with a grinder and finished to a mirror surface. Visual inspection of the welded part for defects. Specifically, the presence or absence of poor penetration of the melted portion, the presence or absence of non-metallic inclusions, the presence or absence of blowholes, etc. are inspected, and the size and number of these defects are recorded. Similarly, the second side end face 12 is also cut thinly and a macro inspection is performed.

  We evaluate welding skills based on the results of ultrasonic testing and macro inspection. By the way, in the macro inspection, it has been described that when the first side end face 11 is cut, it is cut at the cut face 43, but may be cut at other cut faces 45 and 46. The second cut surface 45 is the same surface that is continuous with the second reference surfaces 15b and 15b. The third cut surface 46 is a surface that is cut at the first and fourth steps 14a and 14d. Even when the third cut surface 46 is cut, the first reference surfaces 15a and 15a remain, so that the cut thickness becomes clear and it is guaranteed that it remains as evidence.

  The present invention is not limited to the above embodiment and can be implemented in various forms. For example, the thicknesses of the first and second steel plates do not have to be limited to the present embodiment, and the first to fourth steps can be various sizes. For example, it is possible to make all the first to fourth steps 1 mm. Further, the shape of the groove can be changed, and a baffle plate may be provided in the vicinity of the welding groove. The marking can also be modified, and not only the second reference surface but also the first reference surface may be marked. Furthermore, the first and second side end faces are both provided with a step, but one side end face may be provided with no step. The test piece for skill evaluation according to the present embodiment can be used not only for the purpose of verification but also as a teaching material for practice aimed at improving the skill of welding.

Test piece for 1 skill evaluation
2 1st steel plate 3 2nd steel plate 5 1st end surface for welding 6 2nd end surface for welding 8 Backing metal 9 Welding groove 11 1st side part end surface 12 2nd side part end surface 14a-14d 1st 1 to 4 steps 15a first reference surface 15b second reference surface 16 first contact surface 30, 31 alternative end tab 35 welded portion 38 ultrasonic transmitter

Claims (6)

It is composed of a pair of steel plates connected by a backing metal, and the pair of steel plates is arranged with a gap so that the respective welding surfaces face each other, thereby forming a welding groove filled by welding. And
At least a pair of steps are formed on the end surface perpendicular to the welding groove, whereby the vicinity of the welding groove protrudes outward by a predetermined amount compared to the surroundings. Test piece for skill evaluation in alternative end tab method. 2. The test piece according to claim 1, wherein at least a pair of steps are provided on both end faces perpendicular to the welding groove, whereby the vicinity of both end faces of the welding groove is compared with the surrounding area. A test piece for skill evaluation in an alternative end tab construction method, characterized by protruding outward in a fixed amount. 3. The test piece according to claim 1, wherein one steel plate of the pair of steel plates is thicker than the other steel plate, and the other steel plate has the welding surface cut obliquely, thereby, for the welding. A test piece for skill evaluation in an alternative end tab method, characterized in that a groove having a letter-shaped cross section is formed in the groove. The test piece according to any one of claims 1 to 3, wherein the step is formed to be 0.3 to 1.5 mm. The test piece for skill evaluation in the alternative end tab method. By the test piece according to any one of claims 1 to 4, a method for evaluating the skill of an alternative end tab method,
After contacting a pair of ceramic alternative end tabs on both end faces of the welding groove of the test piece to weld the welding groove, and removing the alternative end tab,
A skill evaluation method in an alternative end tab method, wherein the end face of the test piece is sliced in parallel with the end face at the stepped portion, and the skill is evaluated according to the state of the sliced cross section of the welded part. 6. The skill evaluation method according to claim 5, wherein a welded part is evaluated by an ultrasonic flaw detection method before performing the slicing.

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