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Multiple MAG Repair Welding of Steel S1100QL with the Removal of Defective Fragments of Welds Using Mechanical Treatment

Turyk E., Łomozik M.

Biuletyn Instytutu Spawalnictwa w Gliwicach

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2018

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Vol. 62, No. 5

65--71

EN

The research discussed in the article involved the performance of tests assessing the effect of a one-time and four-time repair welding thermal cycle on mechanical properties of 18 mm thick butt joints made of toughened steel S1100QL. The tests also involved the determination of mechanical properties of a production joint and joints subjected to mechanical treatment-based repair, involving the use of the MAG method (138) and metallic flux-cored wire STEIN-MEGAFIL 1100 M. It was ascertained that the mechanical properties of the joints subjected to mechanical treatment-based repair were similar to those of the joints subjected to repair welding involving the removal of a defective part using arc-air gouging.

PL

Przeprowadzono badania wpływu jedno- i czterokrotnego oddziaływania cyklu cieplnego spawania naprawczego na własności mechaniczne złączy doczołowych blach o grubości 18 mm ze stali ulepszonej cieplnie gatunku S1100QL. Określono własności mechaniczne złącza produkcyjnego oraz złączy naprawianych z użyciem obróbki mechanicznej, wykonywanych metodą MAG drutem elektrodowym proszkowym o rdzeniu metalicznym (proces 138) gatunku STEIN-MEGAFIL 1100 M. Stwierdzono, że własności mechaniczne złączy naprawianych z użyciem obróbki mechanicznej są zbliżone do odpowiednich własności złączy po spawaniu naprawczym z usuwaniem wadliwej części spoiny za pomocą żłobienia elektropowietrznego.

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Mechanical Properties of Welded Joints in Steel S1100QL after Multiple Repair Welding

Łomozik M., Turyk E.

Biuletyn Instytutu Spawalnictwa w Gliwicach

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2018

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Vol. 62, No. 3

7--15

EN

The article presents the use of high-strength toughened steels in various industries and the chronological development of various grades of the above-named steels. In addition, the article discusses the repair of defective fragments of welded joints by means of grinding, grooving or machine cutting followed by the making of a repair weld. Occasionally, the repair process must be repeated or performed many times. An issue of particular importance is the repair welding of steels having a yield point of above 700 MPa. Typically, in structures made of high-strength steels the process of repair consist in the removing of an imperfection (primarily having the form of cracks or porosity) followed by the making of another joint in the area of the previously removed imperfection. The tests described in the article were concerned with flat butt joints made of 18 mm thick toughened steel S1100QL using the MAG method and metallic flux-cored wire grade STEIN-MEGAFIL 1100 M (process 138). The tests involved the making of three welded joints, i.e. one production joint and two joints subsequently subjected to three and four-fold repair welding. In addition, the article presents the methodology and results of transverse tensile tests, transverse bend tests, impact strength tests and hardness tests.

PL

Przedstawiono zastosowanie stali ulepszonych cieplnie o wysokiej wytrzymałości w różnych dziedzinach przemysłu oraz chronologiczny rozwój różnych gatunków tych stali. Scharakteryzowano proces napraw wadliwych fragmentów złączy spawanych, który wiąże się z usuwaniem tych fragmentów przy użyciu szlifowania, żłobienia lub obróbki skrawaniem, a następnie wykonaniem spoiny naprawczej. Niekiedy zachodzi konieczność ponownej lub nawet kilkakrotnej naprawy. Szczególnie istotny problem stanowi spawanie naprawcze stali o granicy plastyczności powyżej 700 MPa. W konstrukcjach ze stali wysokowytrzymałych potrzeba naprawy za pomocą usunięcia wady i wykonania ponownie złącza na odcinku wystąpienia wadliwości zachodzi przede wszystkim w przypadku stwierdzenia wad typu pęknięcia lub porowatość. Przedmiotem badań były złącza doczołowe płaskie stali ulepszonej cieplnie w gatunku S1100QL o grubości 18 mm, spawane metodą MAG przy użyciu drutu elektrodowego proszkowego o rdzeniu metalicznym (proces 138) w gatunku STEIN-MEGAFIL 1100 M. Wykonano trzy złącza spawane, tj. złącze produkcyjne oraz dwa złącza, które następnie poddano trzykrotnemu i czterokrotnemu spawaniu naprawczemu. Przedstawiono także metodykę i wyniki badań tych złączy, które obejmowały próby rozciągania próbek poprzecznych, badanie na zginanie poprzeczne, badanie udarności oraz badanie twardości.

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Welding of MART steel with the use of matching fillers

Matkowski P., Nowacki J., Sajek A.

Archives of Materials Science and Engineering

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2014

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Vol. 70, nr 2

77-86

EN

Purpose: This paper attempts to determine the influence of using fillers of various kinds on strength of a welded joint of MART steel depending on the amount of heat supplied. Design/methodology/approach: Test welded joints were made of S1100QL steel with GMAW method, and using different fillers as well as different values of supplied heat. The tests were designed in such a way so as to demonstrate the prospected interdependencies as clearly as possible. Macroscopic examination was carried out, Vickers hardness, impact strength and tensile strength were measured, and technological bend test was conducted on the joint. Findings: Significant differences between the joints obtained resulting from the fillers used and welding parameters applied were noticed. The strength of a joint is lower than that of welded steel, it concentrates in the weld and is similar to the strength of parent material. Research limitations/implications: Conducting research concentrating on welding using particular filler in a wider range of heat supplied would make it possible to obtain more precise results. By delineating the interdependencies between strength parameters, it would be possible to optimise the mechanical properties of welded joints made of MART steels. It would require the employment of automated welding that allows for unrestricted and stable control of parameters. Practical implications: The conditions for making a proper joint of S1100QL steel were determined. Reasons were given for the choice of joint testing methodology and the purposefulness of comprehensive tests of joint parameters. The need for changing test procedures in order to eliminate the causes of inappropriate evaluation was manifested. The influence of automation as an important factor that determines the fulfilment of strict parameter regime of joint formation was emphasised. Determination of the interrelations between mechanical properties of a joint and welding parameters applied would allow to conduct a welding process in such a way so as to obtain a joint of desired usefulness in given technological conditions. Originality/value: Problems associated with welding of S1100QL steel with the use of filler metals of matching materials were defined and possible solutions for these problems were presented. The mechanism of welding thermal cycle influencing structural changes in the joint that result from the complex cycle of hardening and tempering was demonstrated.