scholarly journals Modelling and optimization of sulfur addition during 70MnVS4 steelmaking: An industrial case study

2021 ◽  
Vol 16 (2) ◽  
pp. 253-261
Author(s):  
M. Kovačič ◽  
B. Lešer ◽  
M. Brezocnik
Keyword(s):  
Chemical Analysis ◽  
Surface Defects ◽  
High Strength ◽  
Ladle Treatment ◽  
Spring Steel ◽  
Melt Processing ◽  
Industrial Case Study ◽  
Cored Wire ◽  
Sulfur Addition ◽  
Steel Cleanliness

Štore Steel Ltd. is one of the major flat spring steel producers in Europe. Among several hundred steel grades, 70MnVS4 steel is also produced. In the paper optimization of steelmaking of 70MnVS4 steel is presented. 70MnVS4 is a high-strength microalloyed steel which is used for forging of connecting rods in the automotive industry. During 70MnVS4 ladle treatment, the sulfur addition in the melt should be conducted only once. For several reasons the sulfur is repeatedly added and therefore threatening clogging during continuous casting and as such influencing surface defects occurrence and steel cleanliness. Accordingly, the additional sulfur addition was predicted using linear regression and genetic programming. Following parameters were collected within the period from January 2018 to December 2018 (78 consequently cast batches): sulfur and carbon cored wire addition after chemical analysis after tapping, carbon, manganese and sulfur content after tapping, time between chemical analysis after tapping and starting of the casting, ferromanganese and ferrosilicon addition and additional sulfur cored wire addition. Based on modelling results it was found out that the ferromanganese is the most influential parameter. Accordingly, 12 consequently cast batches (from February 2019 to October 2019) were produced with as lower as possible addition of ferromanganese. The additional sulfur addition in all 12 cases was not needed. Also, the melt processing time, surface quality of rolled material and sulfur cored wire consumption did not change statistically significantly after reduction of ferromanganese addition. The steel cleanliness was statistically significantly better.

scholarly journals Prediction of Fatigue Limit of Spring Steel Considering Surface Defect Size and Stress Ratio

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 483
Author(s):  
Takehiro Ishii ◽  
Koji Takahashi
Keyword(s):  
Fatigue Limit ◽  
Stress Ratio ◽  
Surface Defects ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Tests ◽  
Spring Steel ◽  
Defect Size ◽  
Small Surface ◽  
Stress Ratios

Surface defects decrease the fatigue limit of metals. In this study, the effects of surface defects on the fatigue limit of high-strength spring steel specimens were investigated. Several equations to predict the fatigue limit of specimens with surface defects were evaluated. Specimens with a semicircular slit with depths ranging from 30 to 400 µm were prepared. The Vickers hardness of the specimen was approximately 470 HV. Bending fatigue tests were performed at stress ratios ranging from −2 to 0.4. The fatigue test results showed that the fatigue limit decreased with an increase in the slit depth. Moreover, the maximum defect size that resulted in a decrease in the fatigue limit was dependent on the stress ratio. On comparing the predicted fatigue limits with the experimental results, it was confirmed that the predictions made based on the modified El-Haddad model were in good agreement with the experimentally obtained data. Thus, this model can be used to evaluate the fatigue limit of high-strength steels containing small surface defects with different stress ratios.

INLAND DURASPRING

Alloy Digest ◽  
1998 ◽  
Vol 47 (5) ◽  
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Tensile Properties ◽  
High Stress ◽  
High Strength ◽  
Spring Steel ◽  
Fatigue Properties ◽  
Light Truck ◽  
Suspension Systems ◽  
Spring Steels

Abstract Inland DuraSpring is a high-strength microalloyed spring steel for use in high stress coil springs for automobile and light truck suspension systems. This bar product offers significant improvements in tensile strength, fatigue properties, and fracture toughness compared to conventional spring steels. This datasheet provides information on composition, hardness, and tensile properties as well asfracture toughness and fatigue. Filing Code: SA-496. Producer or source: Ispat Inland Inc.

scholarly journals Documentation of the Corrosion of Composite-Extruded Aluminium Matrix Extrusions Using the Push-Out Test

2008 ◽  
Vol 43 ◽  
pp. 17-22 ◽  
Author(s):  
Matthias Merzkirch ◽  
Kay André Weidenmann ◽  
Eberhard Kerscher ◽  
Detlef Löhe
Keyword(s):  
Shear Strength ◽  
High Strength ◽  
Spring Steel ◽  
Aluminium Matrix ◽  
Corrosive Media ◽  
Corrosive Attack ◽  
Galvanic Couple ◽  
Space Frames ◽  
Push Out

A possibility to increase both stiffness and strength of aluminium-based structures for the application in lightweight profiles for vehicle space frames is the use of composite extrusions in which high-strength metallic reinforcements are incorporated. Within the scope of the present investigations, composite-extruded profiles with wire-reinforcements made of austenitic spring steel 1.4310 (X10CrNi18-8), in an aluminium matrix AA6060 (AlMgSi0.5), which were exposed to different corrosive media for different times, were characterised in terms of the debonding shear strength using the push-out-technique. The formation of a galvanic couple could be conceived mathematically in regard of terms describing the formation of a shear-impeding layer and the corrosive attack. Thereby the parameters for the different media could be determined.

Achievement of High Ductility and Ultra-high Strength of V-Nb Microalloyed Spring Steel by Austempered Multiphase Microstructure

2020 ◽  
Vol 51 (7) ◽  
pp. 3565-3575 ◽  
Author(s):  
Kui Chen ◽  
Zhouhua Jiang ◽  
Fubin Liu ◽  
Huabing Li ◽  
Congpeng Kang ◽  
...  
Keyword(s):  
High Strength ◽  
Spring Steel ◽  
High Ductility ◽  
Multiphase Microstructure

Flame Retardant Intumescent Polyamide 11-Carbon Nanofiber Nanocomposites: Thermal and Flammability Properties

2007 ◽  
Vol 1056 ◽  
Author(s):  
Si Chon Lao ◽  
Joseph H Koo ◽  
Alexander Morgan ◽  
Hung-Kai Jor ◽  
Khiet Nguyen ◽  
...  
Keyword(s):  
Heat Resistance ◽  
Flame Retardant ◽  
Carbon Nanofiber ◽  
High Strength ◽  
High Heat ◽  
Melt Processing ◽  
Test Method ◽  
Fire Retardancy ◽  
High Heat Resistance ◽  
Polyamide 11

ABSTRACTCurrent polyamide 11 and 12 are lacking in fire retardancy and high strength/high heat resistance characteristics for fabricated parts that are required for performance driven applications. The introduction of selected nanoparticles such as carbon nanofibers (CNFs), combined with a conventional intumescent flame retardant (FR) additive into the polyamide 11/polyamide 12 (PA11/PA12) by melt processing conditions has resulted in a family of intumescent polyamide nanocomposites. These intumescent PA11 and PA12 nanocomposites exhibit enhanced polymer performance characteristics, i.e., fire retardancy, high strength, and high heat resistance and are expected to expand the market opportunities for resin manufacturers. The overall objective of this research is to develop improved PA11 and PA12 polymers with enhanced flame retardancy, thermal, and mechanical properties for selective laser sintering (SLS) rapid manufacturing. Arkema RILSAN® PA11 polymer was examined with CNFs and Clairant Exolit® OP 1230 intumescent FR additive. They were used to create a family of FR intumescent PA11-CNF nanocomposites. Transmission electron microscopy (TEM) was used to determine the degree of CNFs and intumescent FR additive dispersion in PA11. Injection molded specimens were fabricated for material properties measurements. Thermal stability of these polymer nanocomposites (PNs) was examined by TGA. Flammability and thermal properties of these PNs were obtained using the cone calorimeter, UL 94 test method, and heat deflection temperature.

Effect of special combined electromagnetic stirring mode on macrosegregation of high strength spring steel blooms

2008 ◽  
Vol 35 (2) ◽  
pp. 153-156 ◽  
Author(s):  
W.-D. Du ◽  
K. Wang ◽  
C.-J. Song ◽  
H.-G. Li ◽  
M.-W. Jiang ◽  
...  
Keyword(s):  
High Strength ◽  
Spring Steel ◽  
Electromagnetic Stirring

Gigacycle Fatigue Behavior of 1800 MPa Grade High Strength Spring Steel for Automobile Lightweight

2014 ◽  
Vol 21 (6) ◽  
pp. 614-618 ◽  
Author(s):  
Ji-ming Zhang ◽  
Ling-kang Ji ◽  
Dong-jie Bao ◽  
Yao-rong Feng ◽  
Shou-xin Li ◽  
...  
Keyword(s):  
Fatigue Behavior ◽  
High Strength ◽  
Spring Steel

Optimization of a Snap Through Spring for a Hydraulic Valve With Hysteresis Response Behavior

2019 ◽  
Author(s):  
Matthias Scherrer ◽  
Rudolf Scheidl ◽  
Bernhard Manhartsgruber
Keyword(s):  
Ritz Method ◽  
High Strength ◽  
Axial Direction ◽  
Approximate Solutions ◽  
Element Model ◽  
Lateral Force ◽  
Spring Steel ◽  
Nonlinear Buckling ◽  
Buckling Beam ◽  
Compact Design

Abstract The hydraulic binary counter requires switching valves with a hysteretic response. In this paper an elastic snap through element is studied as means for that. The concept is based on a buckling beam which is elastically supported in axial direction in order to adjust its buckling properties with moderate manufacturing precision and to assure a well defined snap through behavior. The elastic support is provided by a cantilever beam. A rigorous optimization is performed heading for a most compact and fatigue durable design which exhibits the required lateral force displacement characteristics. A genetic algorithm is used to find the global design optimum. The stress/displacement properties of each design variant are computed by a compact model of the snap through system. It is derived by a Ritz method to obtain approximate solutions of the nonlinear buckling beam behavior. Its validity is checked by a Finite Element model. A compact design is possible if high strength spring steel is used for the elastic elements.

scholarly journals Tensile and fatigue properties of laser-welded ultra-high-strength stainless spring steel lap joints

2019 ◽  
Vol 36 ◽  
pp. 131-137 ◽  
Author(s):  
Mikko Hietala ◽  
Antti Järvenpää ◽  
Markku Keskitalo ◽  
Matias Jaskari ◽  
Kari Mäntyjärvi
Keyword(s):  
High Strength ◽  
Lap Joints ◽  
Spring Steel ◽  
Fatigue Properties
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