Simulation And Experimental Results Of The Hot Metal Gas Forming Technology For High Strength Steel And Stainless Steel Tubes Forming

The present study consists of a theoretical, experimental and fractographic investigation of the effect of superimposed static axial and shear stresses on the high cycle fatigue behavior of a 34CrNiMo6 high strength steel in quenched and tempered condition (UTS = 1210 MPa), commonly employed in highly stressed mechanical components. The Haigh diagrams for the axial and torsional cases under different values of mean stress were obtained. In both cases, experimental results showed that increasing the mean stress gradually reduces the stress amplitude that the material can withstand without failure. The results of the present tests are compared with the theoretical predictions from Findley, based on the maximum damage critical plane; and the methods of Marin and Froustey, which are energetic based criterions. Froustey’s method shows the best agreement with experimental results for torsional fatigue with mean shear stresses, showing a non-conservative behaviour for the axial fatigue loading case. Macro-analyses and micro-analyses of specimen fracture appearance were conducted in order to obtain the fracture characteristics for different mean shear stress values under torsion fatigue loading.

Download Full-text

Influence of Lubricants on Advanced High Strength Steel Tubes in Bending Process

Volume 4: Design and Manufacturing ◽

10.1115/imece2009-13321 ◽

2009 ◽

Cited By ~ 1

Author(s):

Ramakrishna Koganti ◽

Sergio Angotti ◽

Isadora van Riemsdijk ◽

Robert C. Nelson ◽

Jill Smith

Keyword(s):

High Strength Steel ◽

High Strength ◽

Steel Tube ◽

Application Site ◽

Structural Components ◽

Advanced High Strength Steel ◽

Steel Tubes ◽

Automotive Body ◽

Bending Process ◽

Lubricant Performance

To reach safety, emissions, and cost objectives, manufacturers of automotive body structural components shape thin gauge, high strength steel tube using a series of manufacturing steps that often include bending, preforming and hydroforming. Challenging grades and bend severity require a sensitive optimization of the tubular bending process. Lubricants play a significant role in establishing a successful bending process. In this study, the performance of two lubricants, Hydrodraw 551 and HFO 20, were investigated for bending Dual Phase 780 (DP780) and High Strength Low Alloy 350 (HSLA350) thin-walled steel tubes. Formability success was evaluated in terms of wrinkling, thinning strain and final geometry. Lubricant performance was found to be sensitive to grade and application site. HFO 20 was found to be a poor choice for bending DP780 tube.

Download Full-text

Compressive Properties of High Strength Steel Fiber Reinforced Concrete with Different Fiber Volume Fractions

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.372.215 ◽

2013 ◽

Vol 372 ◽

pp. 215-218 ◽

Cited By ~ 2

Author(s):

Hye Ran Kim ◽

Seung Ju Han ◽

Hyun Do Yun

Keyword(s):

Compressive Strength ◽

Reinforced Concrete ◽

High Strength Steel ◽

Steel Fiber ◽

High Strength ◽

Fiber Reinforced Concrete ◽

Experimental Results ◽

Steel Fiber Reinforced Concrete ◽

Fiber Volume ◽

Volume Fractions

This paper describes the experimental results of 70 MPa high strength steel fiber reinforced concrete (SFRC) with different steel fiber volume fractions in compression. The effect of steel fiber on fresh properties, compressive strength, toughness index, cracking procedure of high strength steel fiber concrete is also investigated. The steel fibers were added as the volume fractions of 0%, 0.5%, 1.0%, 1.5% and 2.0%. The cylindrical specimens with Φ100 x 200 for compressive tests were manufactured in accordance with ASTM C 39[. The experimental results showed that the slump of fresh SFRC was inversely proportional to the fiber volume fraction added to high strength concrete. As the addition of steel fiber increased, compressive strength of SFRC decreased. Inclusion of steel fiber improves compressive toughness of high strength SFRC.

Download Full-text

Experimental Study on Bearing Capacity of Q690 High-Strength Steel Tubes under Axial Load

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.638-640.101 ◽

2014 ◽

Vol 638-640 ◽

pp. 101-104

Author(s):

Yi Liang Peng ◽

Guo Tian Li ◽

Xuan Min Han ◽

Lei Chen

Keyword(s):

Experimental Study ◽

Bearing Capacity ◽

High Strength Steel ◽

Axial Load ◽

High Strength ◽

Steel Grade ◽

Stability Factor ◽

Steel Tubes ◽

Steel Members ◽

The Stability

With the rapid development of power transmission and transformation projects in China, steel supporting structure has already became the most popular structural form for these structures. However, the limit of steel grade used for current substation supporting structures is normally Q420, compared with that of Q690 used in other countries. When the high-strength steel is used, the geometric parameters of section for members become smaller, and the stability of members is the most important factors to influence the bearing capacity of structures. The stability factor for axial loaded steel members in current 《Code for design of steel structures》(GB50017-2003) was derived based on the experimental results for steel members with lower steel grade, the results are inevitably different from those for high-strength steel members. To make the calculations of Q690 high-strength steel tubes more accurate and reasonable, this paper conducts experimental study on the bearing capacity of Q690 high-strength steel tubes under axial load to provide scientific basis for practical design of these structures.

Download Full-text

Forming Limits of Several High-Strength Steel Sheets under Proportional/Non-Proportional Deformation Paths

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.939.260 ◽

2014 ◽

Vol 939 ◽

pp. 260-265 ◽

Cited By ~ 2

Author(s):

Ryutaro Hino ◽

Satoki Yasuhara ◽

Yutaka Fujii ◽

Atsushi Hirahara ◽

Fusahito Yoshida

Keyword(s):

High Strength Steel ◽

High Strength ◽

Experimental Results ◽

Forming Limit ◽

Type Analysis ◽

Forming Limits ◽

Steel Sheets ◽

Path Dependent ◽

Forming Limit Curves ◽

Good Agreement

Forming limits of several high-strength steel (HSS) sheets under non-proportional deformation paths were examined experimentally and predicted analytically. Forming limit curves (FLCs) for 590MPa, 780MPa and 980MPa grade HSS sheets were obtained by performing stretch forming tests under proportional deformation and two types of non-proportional deformation. The experimental results showed strong path-dependent characteristics of FLCs of HSS sheets. Forming limits of equi-biaxially prestrained HSS sheets became markedly lower compared to the original FLCs under proportional deformation, while forming limits of uniaxially prestrained HSS sheets became partially higher than the original FLCs. It was confirmed that Marciniak-Kuczyński type analysis gave reasonably good predictions of forming limits under non-proportional deformation paths. Especially forming limit predictions of equi-biaxially-prestrained sheets showed good agreement with the corresponding experimental results.

Download Full-text