Improvement of fatigue endurance of welded S355 J2 structural steel by severe shot peening

Abstract

This work deals with the fatigue resistance of welded joints manufactured from EN S355 J2 structural steel and the possibility of improving fatigue characteristics by the severe shot peening (SSP) surface treatment. Fatigue testing was carried out by the rotating bending test on specimens manufactured from the base material (BM), welded material and welded material treated by SSP. Results have shown big scatter in obtained results from as-welded material and overall reduction of fatigue endurance when compared to the BM. SSP applied on the welded joints has reduced the scatter of experimental data and increased the fatigue strength. Obtained results of fatigue tests are compared, discussed and supported by correlation with results of additional experiments, e.g. metallographic analyses, microhardness tests, residual stresses measurements and surface roughness measurement.

Fatigue Life Improvement of the High Strength Steel Welded Joints by Ultrasonic Impact Peening

“…Since the rotating bending loading is carried out by symmetrical four-point bending, the loading stress is constant in the gauge length of the specimen [18]. This assures the constant loading value of all the welded joint zones from the weld metal (WM) through the heat affected zone (HAZ) to the base metal (BM) [19]. Specimens in as-welded conditions were ground using the grinding papers up to the #1200, to eliminate the surface roughness created during the specimens machining.…”

Editorial: special issue on shot peening

“…A great deal of research has been carried out to study the effects of SP on the materials being treated, including metallurgical, mechanical, and geometrical effects and also the effects of SP on the mechanical properties, tribological characteristics and corrosion resistance of a wide range of metals and alloys. Recently advanced surface modification technologies show the use of variants of the traditional SP process, four of which are shown in this issue, namely Ultrasonic SP [1,2], Severe SP (SSP) [3], Surface Mechanical Attrition Treatment (SMAT) [4] and duplex SP [5]. Other variants of SP can be found in literature, including Laser Shock Peening (LSP), Micropeening, Cavitation Shotless Peening and Ball or Roller Burnishing.…”

“…The improvements resulting from the SP process on a variety of base materials, ranging from solid metals to alloys are discussed. These materials include austenitic stainless steel [4], AISI 1018 [1] and 4340 steel [5], S355 J2 structural steel [3], X65 steel [2], precipitation hardened ultrafine-grained copper alloy [6], austempered ductile iron [7] and Vitreloy 105 bulk metallic glass [8]. Yin et al [1] perform mathematical modelling and simulations of the kinetics of the process to predict the resulting surface topography of peened samples.…”

Análise Do Alívio Térmico De Tensões Residuais Do Aço Sae 4140 Por Difração De Raios-X Fast in-Situ

“…Observa-se que a mudança mais significativa na distribuição das T R ocorre na região superficial da estrutura tratada [12]. Medições in-situ já foram empregadas com sucesso por diversos pesquisadores para investigar propriedades de materiais [13], tais como transformações de fases [14], análise de fases [15] e T R [16], através de estudos analíticos, experimentais e computacionais [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][22][23][24][25]. Uma pesquisa cuja análise foi relacionada à relaxação das T R C induzidas por SP e a redistribuição, durante ensaios em regime de flexão rotativa de alto e de baixo ciclos em aço carbono (0,45%C 16.…”

“…Em contraponto, há o efeito deletério das T R C relaxarem em serviço, na presença de certos elementos cruciais e cotidianos, tais como: alta temperatura (T), cargas mecânicas (cíclicas ou não) / térmicas ou termomecânicas [3]. Além disso, a rugosidade produzida por SP pode danificar a superfície, gerando concentradores de tensões [4]. A rugosidade superficial por SP aumenta com o aumento da intensidade dos tiros.…”