Introduction to a Third-Generation Automobile Steel and Its Optimal Warm-Stamping Process

2015 ◽  
Vol 138 (4) ◽  
Author(s):  
Ying Chang ◽  
Cunyu Wang ◽  
Kunmin Zhao ◽  
Han Dong ◽  
Jianwen Yan
Keyword(s):  
Tensile Strength ◽  
Third Generation ◽  
Range Analysis ◽  
Forming Process ◽  
Soaking Time ◽  
Stamping Process ◽  
Medium Mn Steel ◽  
Automobile Steel ◽  
Formed Part ◽  
Mn Steel

The medium-Mn steel is a promising third-generation automobile steel. Its chemical composition, microstructure, and thermal and mechanical properties are introduced and a warm-stamping process for the medium-Mn steel is proposed. The optimal process parameters are identified through the design of experiments (DOE) and range analysis. The evaluated experimental indexes include tensile strength, elongation, and hardness. The optimal forming process consists of an austenitization temperature of 840 °C, a soaking time of 4 min, and an initial stamping temperature of 500 °C. The proposed process was applied to the warm stamping of an automotive B-pillar. The microstructure of ultrafine, uniform, and complete martensite laths was obtained. The formed part exhibits approximately 1420 MPa tensile strength, over 11% elongation and 460 HV hardness. The optimal warm-stamping process has proved effective and applicable for forming medium-Mn steel parts. It will help promote the application of the third-generation automotive steels.

Investigation on Microstructure and Martensitic Transformation Mechanism for the Warm-Stamped Third-Generation Automotive Medium-Mn Steel

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Xiaodong Li ◽  
Ying Chang ◽  
Cunyu Wang ◽  
Shuo Han ◽  
Daxin Ren ◽  
...  
Keyword(s):  
Martensitic Transformation ◽  
Strain Rate ◽  
Compressive Load ◽  
High Strength ◽  
Third Generation ◽  
Transformation Mechanism ◽  
Loading Method ◽  
Strain And Strain Rate ◽  
Medium Mn Steel ◽  
Mn Steel

With the development of the automotive industry, the application of the high-strength steel (HSS) becomes an effective way to improve the lightweight and safety. In this paper, the third-generation automotive medium-Mn steel (TAMM steel) is studied. The warm-stamped TAMM steel holds the complete and fine-grained martensitic microstructure without decarbonization layer, which contributes to high and well-balanced mechanical properties. Furthermore, the martensitic transformation mechanism of the TAMM steel is investigated by the dilatation tests. The results indicate that the effects of the loading method on the Ms temperature under different loads are different. The Ms temperature is hardly influenced under the tensile loads and low compressive load. However, it is slightly decreased under the high compressive load. Moreover, the effects of the strain and strain rate on the Ms temperature are insignificant and can be neglected. As a result, this research proves that the martensitic transformation of the TAMM steel is rarely influenced by the process parameters, such as stamping temperature, loading method, load, strain, and strain rate. The actual stamping process can be designed and controlled accurately referring to the continuous cooling transformation (CCT) curves to realize the required properties and improve the formability of the automotive part.

Simulation Study on the Austenisation and Cooling Behaviors of the Medium-Mn Steel

2014 ◽  
Vol 1063 ◽  
pp. 3-6 ◽  
Author(s):  
Si Lian Chen ◽  
Yao Zong Bao ◽  
Han Dong ◽  
Wen Quan Cao
Keyword(s):  
Tensile Strength ◽  
Chemical Composition ◽  
Hot Stamping ◽  
Total Elongation ◽  
Air Cooling ◽  
Car Industry ◽  
Medium Mn Steel ◽  
Hot Stamping Steel ◽  
Mn Steel ◽  
Holding Temperature

The austenisation and quenching behaviors of a medium-Mn steel with a chemical composition of C 0.14% and Mn 5.0% were presented in this paper. The heating and holding temperature varied from 500OC to 950OC was applied to find the austenization temperature. The holding time varied from 1-5minutes was used to choose the suitable austenisation time. Air cooling were applied to check the hardening capacity of the studied steel. It was found that the tensile strength is lower than 900Mpa and total elongation varied from 20-30% when the austenisation temperature is lower than 700OC. However, the tensile strength could be high up to 1600MPa and the total elongation about 12% when the austenisation temperature is higher than 700OC with air cooling. Based on the low austenisation temperature and the air hardening capacity, it was proposed that the studied medium-Mn steel could be used as the hot stamping steel in the car industry.

Effect of austenite reverted transformation-annealing heat treatment on microstructure and mechanical properties of Fe–0.14C–5Mn–1Al–Ce steel

2021 ◽  
pp. 095440892110362
Author(s):  
Zhenjiang Li ◽  
Yujing Liu ◽  
Pengju Jia ◽  
Chao Luo ◽  
Ruyi Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Microstructure And Mechanical Properties ◽  
Medium Mn Steel ◽  
The Matrix ◽  
Annealing Heat Treatment ◽  
Mn Steel ◽  
Martensite Structure

Microstructure and mechanical properties of medium-Mn steel (Fe–0.14C–5Mn–1Al–Ce) processed by different austenite reverted transformation-annealing temperatures vary from 580 °C to 740 °C were studied. It was found that the austenite reverted transformation-annealing temperature has a strong effect on microstructure evolution. The martensite structure was transformed into austenite by austenite reverted transformation during the austenite reverted transformation-annealing process. The orientation relationship between the austenite and the matrix was dominated by the Kennicutt–Schmidt relation. With the increase of the austenite reverted transformation-annealing temperature, the content of retained austenite first increases and then decreases at room temperature. The tensile strength first decreases and then increases, while the elongation first increases and then decreases. An excellent combination of tensile strength and elongation (Rm × A) was obtained in the Fe–0.14C–5Mn–1Al–Ce steel by austenite reverted transformation-annealing at 640 °C.

A novel cold-rolled medium Mn steel with an ultra-high product of tensile strength and elongation

2020 ◽  
Vol 258 ◽  
pp. 126804 ◽  
Author(s):  
Feng Yang ◽  
Jian Zhou ◽  
Yun Han ◽  
Peng Liu ◽  
Haiwen Luo ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Medium Mn Steel ◽  
Cold Rolled ◽  
Mn Steel

Effects of Different Cutting Processes on Characteristics of Cut Damage for the Third-Generation Automobile Medium-Mn Steel

2017 ◽  
Vol 89 (9) ◽  
pp. 1700375 ◽  
Author(s):  
Ying Chang ◽  
Shuo Han ◽  
Xiaodong Li ◽  
Cunyu Wang ◽  
Guojun Zheng ◽  
...  
Keyword(s):  
Third Generation ◽  
The Third ◽  
Medium Mn Steel ◽  
Cutting Processes ◽  
Mn Steel

A Comparative Study on Formability of the Third-Generation Automotive Medium-Mn Steel and 22MnB5 Steel

2018 ◽  
Vol 27 (2) ◽  
pp. 530-540 ◽  
Author(s):  
Guojun Zheng ◽  
Xiaodong Li ◽  
Ying Chang ◽  
Cunyu Wang ◽  
Han Dong
Keyword(s):  
Comparative Study ◽  
Third Generation ◽  
The Third ◽  
22Mnb5 Steel ◽  
Medium Mn Steel ◽  
Mn Steel
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