|Quality||Yield point Rp0,2 |
|Tensile strength Rm |
|CR1||140 - 300||270 - 410||≥30||≥28||≥30|
|CR2||140 - 240||270 - 370||≥34||≥34||≥37||≥1,3||≥1,2||≥0,16|
|CR3||140 - 210||270 - 350||≥38||≥38||≥41||≥1,8||≥1,5||≥0,18|
|CR4||140 - 180||270 - 330||≥40||≥39||≥42||≥1,9||≥1,6||≥0,20|
|CR5||110 - 170||260 - 330||≥42||≥41||≥45||≥2,1||≥1,8||≥0,22|
|HR0||240 - 350||310 - 460||≥26||≥22||≥24||≥0,12|
|HR2||180 - 290||270 - 400||≥32||≥30||≥33||≥0,16|
Mild Steels according to VDA 239-100
The German Association of the Automotive Industry (VDA) has published a recommendation for steel flat products for cold forming. The recommendation appears in the new standard VDA 239-100 and starts with the mild steels, e.g. CR3, CR4 and CR5.
With their low yield strength and high elongation point, soft deep-drawing steels are particularly suitable for the manufacturing of complex components. The elongation is characterized by a minimum value; In addition, the CR2, CR3, CR4 and CR5 minimum values for the vertical anisotropy (r-value) and guaranteed solidification exponent (n-value). Typical applications are demanding exterior body and interior body parts such as fenders, sidewall frames, floor panels, spare wheel wells and door outer and inner panels.
Mild steels from the VDA 239-100 leaflet can be manufactured as non-IF or IF steels. As a result they have an even better ductility, extremely low carbon and nitrogen contents. The stabilization gets done by the addition of titanium and / or niobium. These deep drawing steels showing a purely ferritic microstructure or consist of a ferritic matrix into which isolated granular carbides can be incorporated.
Nomenclature of mild steels according to VDA 239-100
CR = kaltgewalzt
HR = warmgewalzt
|0 = Grundgüte|
|1 = Ziehgüte|
|2 = Tiefziehgüte|
|3 = Sondertiefziehgüte|
|4 = Spezieltiefziehgüte|
|5 = Supertiefziehgüte|
Out of hte above listed nomenclature, the desired steel can freely put together. The short name is a combination of the the rolling type (hot or cold strip) and the grade class number 1 to 5. As the number of grades increases, the formability improves. The chemical concept of steel can be specified by adding “IF” or “Non-IF”. IF steels have a very low carbon content, usually less than 0.02% to improve the forming ability. Without this supplement, the manufacturer is free to use the alloy concept within the framework of the VDA 239-100 specifications .
In addition, the mild steels can also be produced in a coated variant. You can find more about this under the menu item Surfaces and Coatings. (Insert link)
For example, a coated version could be named as follows.
VDA 239-100 – CR4 + GI40 / 40-U
Mild cold-rolled steel, grade 4, hot-dip galvanized with a coating weight of at least 40 g/m² per side, surface quality for internal parts.
At the top table of this page you can find the first details of mild steels of the VDA. You can also download the excerpt from our Quality Guides (QG) with the mechanical and chemical values for the VDA239-100 via the previous link.
All presented steel grades can be supplied as coil, slitted coils, sheets and blank.
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