Boron-Treated High Strength Structural Steels and Their Application to Automotive Components

1983 ◽  
Author(s):  
Fukukazu Nakasato ◽  
Michitaka Fujita ◽  
Kazuhiko Nishida ◽  
Hiroo Ohtani ◽  
Tetsu Ohno
Keyword(s):  
High Strength ◽  
Structural Steels ◽  
Automotive Components

Usability Testing of Ultra High-Strength Steels

2012 ◽  
Author(s):  
Jouko A. Heikkala ◽  
Anu J. Väisänen
Keyword(s):  
Tensile Strength ◽  
Plate Thickness ◽  
Rolling Direction ◽  
High Strength Steels ◽  
High Strength ◽  
Structural Steels ◽  
Test Material ◽  
Material Strength ◽  
Machining Parameters ◽  
Usability Tests

New ultra high strength (UHS) steels have been developed in order to get advantages in machine design and construction. Following benefits can be obtained for example: - less material usage due to lighter constructions; - better payload and less fuel consumption in vehicle industry; - energy saving in material production. A rough distinction of structural steels can be defined to ductile steels, with tensile strength less than 300 MPa, and high strength steels, up to 700 Mpa. A steel material can be defined as UHS steel when the tensile strength exceeds 700 MPa. Steels with yield strength of 1500 Mpa have been developed so far. UHS steels can also be divided into structural steels and wear resistant steels. With the tensile strength also the hardness increases and the tensile strain decreases. That causes several difficulties when the material is processed into products. Especially mechanical processing like bending, machining and shearing gets difficult as the material strength increases. That causes problems for the construction material users to find the proper manufacturing methods in production. In Oulu University Production Technology Laboratory material processing tests have been performed during several years in co-operation with the local steel manufacturer. The usability tests comprise mainly of bending and machining tests. Shearing and welding tests have been made to a smaller extent. Also laser treatment has been used for local heat conditioning in order to improve the bending and shearing properties, but these techniques are not yet widely used in production. The bending tests are carried out with standard bending tools and test steel plates with standard dimensions. The plate thickness varies depending on the test material. The target is to determine the reliable minimum bending radiuses whereby the plate can be bent without failure, from both sides and along the rolling direction and orthogonally to that. Also the springback angle is measured and the bent surfaces are evaluated according to several criteria. When necessary, also the mechanical testing of the formed material is carried out. The machining tests are made mainly by drilling. Also some milling tests have been performed. Drilling is a convenient way of machining testing because a substantial amount of holes can be drilled in one test plate. The drilling power can be observed precisely by monitoring the spindle power. Also a variety of different tool types can be used, from uncoated HSS drills to boring tools with indexable inserts. The optimal machining parameters (feed and speed) will be defined according to maximum tool life and minimum machining costs.

Surface Engineering Techniques and Applications

2014 ◽  
pp. 73-101
Author(s):  
Dharam Persaud-Sharma
Keyword(s):  
Surface Engineering ◽  
Weight Ratio ◽  
High Strength ◽  
Orthopedic Implants ◽  
Strength Properties ◽  
Automotive Components ◽  
Hydroxide Film ◽  
Important Challenge ◽  
Cast Magnesium ◽  
Bone Structures

Magnesium and its alloys are a well-explored type of material with a multitude of applications ranging from biomedical prosthetics to non-biological tools such as automotive components. The use of magnesium and its alloys are highly desired for such applications mainly because magnesium is lightweight and possesses a high strength to weight ratio, which reduces the amount of energy required for the operation of an apparatus. In particular, the biomedical industry uses magnesium as orthopedic implants because of its strength properties that are similar to organic bone structures. Additionally, the highly corrosive or degrading nature of magnesium makes it suitable for degradable implants or medical devices. Cast magnesium alloys are also used as components in modern engines and automobiles, as magnesium's lightweight and high strength properties permit for faster automotive speeds, acceleration, and reduced energy consumption. Magnesium produces a quasi-passive hydroxide film that offers little to no inhibition of corrosion processes. Although the degree of film passivity can be increased through metallurgical techniques like alloying, the highly oxidizing nature of magnesium remains the single most important challenge to its widespread use. This chapter provides a detailed explanation of the most successful mechanisms used to control the corrosion of magnesium and its alloys and highlights the benefits and challenges for using them.

scholarly journals Hydrogen-assisted cracking in GMA welding of high-strength structural steels using the modified spray arc process

2020 ◽  
Vol 64 (12) ◽  
pp. 1997-2009
Author(s):  
Thomas Schaupp ◽  
Michael Rhode ◽  
Hamza Yahyaoui ◽  
Thomas Kannengiesser
Keyword(s):  
Weld Metal ◽  
Gma Welding ◽  
High Strength ◽  
Economic Benefits ◽  
Structural Steels ◽  
Test Series ◽  
Deposition Rates ◽  
The Past ◽  
Hydrogen Assisted Cracking ◽  
Implant Test

Abstract High-strength structural steels are used in machine, steel, and crane construction with yield strength up to 960 MPa. However, welding of these steels requires profound knowledge of three factors in terms of avoidance of hydrogen-assisted cracking (HAC): the interaction of microstructure, local stress/strain, and local hydrogen concentration. In addition to the three main factors, the used arc process is also important for the performance of the welded joint. In the past, the conventional transitional arc process (Conv. A) was mainly used for welding of high-strength steel grades. In the past decade, the so-called modified spray arc process (Mod. SA) has been increasingly used for welding production. This modified process enables reduced seam opening angles with increased deposition rates compared with the Conv. A. Economic benefits of using this arc type are a reduction of necessary weld beads and required filler material. In the present study, the susceptibility to HAC in the heat-affected zone (HAZ) of the high-strength structural steel S960QL was investigated with the externally loaded implant test. For that purpose, both Conv. A and Mod. SA were used with same heat input at different deposition rates. Both conducted test series showed same embrittlement index “EI” of 0.21 at diffusible hydrogen concentrations of 1.3 to 1.6 ml/100 g of arc weld metal. The fracture occurred in the HAZ or in the weld metal (WM). However, the test series with Mod. SA showed a significant extension of the time to failure of several hours compared with tests carried out with Conv. A.

Microstructure Evolution of a HSLA Offshore Steel with Cooling Rates

2012 ◽  
Vol 583 ◽  
pp. 306-309
Author(s):  
Yan Tang Chen ◽  
Kai Guang Zhang ◽  
Ji Hao Cheng
Keyword(s):  
Cooling Rate ◽  
Steel Plate ◽  
Hsla Steel ◽  
High Strength ◽  
Structural Steels ◽  
Steel Making ◽  
Offshore Engineering ◽  
Hsla Steels ◽  
Rolling Experiment ◽  
Final Rolling

The high strength low alloy (HSLA) steels have been extensively used in offshore engineering. The appropriate microstructure of the HSLA structural steels was designedly controlled in steel making for offshore construction. The different microstructures of the steel were formed when shifted the cooling rate after final rolling. Experiment results shown that ferrite and pearlite were observed in the HSLA steel with a cooling rate less than 0.2°C/s. Bainite was formed when the cooling rate ranged from 1.0°C/s to 5.0°C/s and martensite was seen in the steel plate with a cooling rate more than 30°C/s. Generally the martensite is a prohibited product in the offshore structural steels.

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