High strength IF steels

Transcription

1 Automotive Worldwide High strength IF steels Extract from the product catalogue -European edition Note: Information contained in this catalogue is subject to change. Please contact our sales team whenever you place an order to ensure that your requirements are fully met. Please contact us if you have a specific requirement that is not included in the range of products and services covered by this catalogue. We are also reachable by the address automotive.request@arcelormittal.com.

2 High strength IF steels High yield and tensile strength steels Description These steels were designed to provide an excellent combination of drawability and mechanical strength based on their specific interstitial free (IF) metallurgy. IF180 offers drawability similar to that of ArcelorMittal 04 combined with tensile strength comparable to that of H220, for example. These steels are hardened by adding manganese, silicon and phosphorous in solid solution to the ferrite. The metallurgy of IF steels optimizes their drawability. Their low YS/UTS ratio and high strain hardening coefficient n ensure excellent deep-drawability and good strain redistribution. Their high strain ratio r ensures good deformation behavior, making them suitable for deep-drawing. These steels are particularly suitable for complex parts requiring high mechanical strength, such as wheel arches, toe-boards, reinforcements, etc. These steels have high strain hardening potential during forming, lending deep-drawn parts (trunks, tailgates, doors, linings, wheel arches, etc.) good dent resistance. The IF180 to grades can be used, with certain coatings, to manufacture visible parts such as door panels. The grade is designed for more complex structural parts (longitudinal beams, cross members, suspension and chassis components, etc.). Application With their high mechanical strength guaranteeing good fatigue and impact resistance, these steels are intended for structural parts (longitudinal beams, cross members, B-pillars, etc.) as well as for skin parts, in which they provide good indentation resistance. In contrast to that of conventional drawing qualities, the weight reduction potential of these products increases with drawing depth. Hood in IF220 Extragal (thickness: 0.7 mm) Designation and standard IF 180 Euronorms VDA HC180Y (+ZE) /HX180YD (+Z, +ZF, HC220Y (+ZE) /HX220YD (+Z, +ZF, HC260Y (+ZE) /HX260YD (+Z, +ZF, /HX300YD (+Z, +ZF, CR180IF (-UNC,-EG,-GI,-GA,-ZM) CR210IF (-UNC,-EG,-GI,-GA,-ZM) CR240IF (-UNC,-EG,-GI,-GA,-ZM) 2

3 Euronorms Uncoated ( EN 10268: 2006+A1: 2013): Steel grade name Electrogalvanized (EN :2006+A1: EN :2017): Steel grade name +ZE Galvannealed (EN :2015): Steel grade name +ZF Extragal /Ultragal for visible parts (EN :2015): Steel grade name +Z Zagnelis (EN :2015): Steel grade name +ZM VDA Uncoated: Steel grade name-unc Electrogalvanized: Steel grade name-eg Galvannealed: Steel grade name-ga Extragal /Ultragal for visible parts: Steel grade name-gi Zagnelis : Steel grade name-zm While the ArcelorMittal grades conform perfectly well to the indicated EN standards, ArcelorMittal grades generally offer tighter mechanical properties (see table below). The above indicative table summarizes the European and VDA standards corresponding to the ArcelorMittal product range. Technical characteristics Mechanical properties Guaranteed for ISO 20x80 specimen of uncoated sheet in the transverse direction PS 0,2 (MPa) UTS (MPa) e f (%) L 0 = 80 mm th < 3 mm IF ,7 0, ,7 0, ,5 0, ,5 0,17 r n Chemical composition (%) C Mn Si Max Max Max IF 180 0,010 1,00 0,25 0,010 0,70 0,50 0,010 1,00 0,50 0,010 1,00 0,50 Available coatings and Worldwide availability Uncoated Electrogalvanized Extragal EUR NAM SAM RSA CHI EUR NAM SAM RSA CHI EUR NAM SAM RSA CHI IF 180 3

4 IF 180 Ultragal Galvannealed Zagnelis EUR NAM SAM RSA CHI EUR NAM SAM RSA CHI EUR NAM SAM RSA CHI Available in non-visible part quality Undergoing customer testing Under development Available in visible and non-visible part quality (Z) EUR : Europe Region -NAM : North America Region -SAM : South America Region -RSA : South Africa Region -CHI : China X Available - XX Available in visible part quality Microstructure of IF 180 Recommendations for use and secondary processing Forming IF steels offer excellent drawability for their strength level as a result of their very good fracture elongation, normal strain ratios and strain hardening coefficients. The diagram opposite shows examples of forming limit curves for the IF family of steels in 1.00 mm thickness. Forming limit curves calculated for IF 180 and 260 steels (thickness: 1.0 mm) ArcelorMittal has an extensive database on the forming of IF steels. To integrate these steels at the design stage, a team of experts is available to carry out specific studies based on modeling or shop-floor experience. 4

5 Welding IF steels can be readily welded by all welding processes. The table below shows examples of spot welding parameters according to the ISO method for products in the IF range: IF 180 Galvannealed (thickness: 2 mm) Extragal (thickness: 1 mm) Welding range (ka) 1,8 1,4 Based on long experience in the spot and arc welding characterization of its products, ArcelorMittal can provide technical assistance in adjusting the welding parameters of any other product in the IF range. Fatigue strength Fatigue strength can be expressed as an endurance limit (maximum stress). Examples of Wöhler curves for a variety of IF steels are given in the graph below. The curves plot maximum stress versus number of cycles to failure. They are calculated for a tension-compression loading ratio of R = 0.1. Wöhler curves for a variety of IF steels ArcelorMittal has a comprehensive database on the fatigue performance of IF steels. ArcelorMittal Last update: