High-strength and ultrahigh-strength. Cut sheet from hot-rolled steel strip and heavy plate. voestalpine Steel Division

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1 High-strength and ultrahigh-strength TM steels Cut sheet from hot-rolled steel strip and heavy plate Josef Elmer, Key account manager voestalpine Steel Division

2 Weight savings and optimized weldability: We supply light-weight solutions for a successful future. 2

3 High-strength and ultra-highstrength steels by voestalpine Successful light-weight design requires the utilization of high-strength and ultra-high-strength steels. The innovative thermomechanically (TM) rolled steel grades alform and alform x-treme made by voestalpine lead to comprehensive weight reduction and provide exceptional advantages in processing. High-strength and ultra-high-strength alform steels are available as hot-rolled strip or as cut sheets made from hot-rolled steel strip and heavy plate. Convincing advantages Excellent weldability Excellent cold formability Best cuttability Perfect surface Excellent toughness 3

4 Efficient light-weight construction Less is more The central objective is to achieve decreased material thickness at the same performance level and to increase the performance level with unchanged dimensions. Both objectives are optimally achievable with high-strength and ultra-high-strength alform and alform x-treme steels made by voestalpine. The application of high-strength and ultra-high-strength alform steels makes it possible, depending on the load, to reduce material thicknesses and thus the weight by up to 70%. In addition, not only the weight is decreased, but the costs are diminished as well. Weight savings through application of high-strength and ultra-high-strength alform steels Weight [%] Minimum yield strength [MPa] Load Dynamic Static Customer benefits Higher lifting and load capacity, lower dead weight Higher environmental compatibility, lower fuel consumption and less ground compression Costs reduced by less material usage and reduction in filler materials 4

5 Typical applications Mobile cranes Loader cranes Concrete pumps Commercial vehicles Railcars Containers Agricultural and forestry machinery Offshore platforms Penstocks 5

6 Reduced costs Savings with high-strength and ultra-high-strength steels The reduced material thicknesses, light weight and smaller volumes of high-strength and ultra-high-strength steels provide cost savings from procurement to manipulation and processing. Procurement Manipulation Processing Smaller volumes and less weight lead to reduced transportation costs. Low unit weights make it possible to use smaller transport units and lifting devices. Reduced material thicknesses lower the costs for: Welding Fewer filler materials required Shorter welding times Laser cutting Shorter laser cutting times 6

7 Potential savings in rectangular sections (example) The potential savings in high-strength and ultra-high-strength alform steel grades depend on the specific application. The following example shows how the potential savings increase as high-strength and ultra-high-strength steels are implemented step by step in a bending beam under static load. The actually achieved reduction in material thickness depends both on the static/dynamic load and the structural conditions (positions of weld seams, notches, etc.). Sheet thickness: 73% Weld seam volume: 93% S355J2C (sheet thickness 15 mm) alform 960 x-treme (sheet thickness 4 mm) Steel grade comparison Rectangular section 120 mm x 80 mm x thickness, longitudinally welded, V seam, bending moment 50 knm Steel grade S355J2C alform 700 M alform 960 x-treme Sheet thickness 15 mm 6 mm 4 mm Weld seam volume 100% 16% 7% Laser cutting time 100% 40% 27% Required edge force 100% 32% 19% Minimum inside edge radius 100% 23% 30% Component weight 100% 44% 30% Component costs are drastically reduced by lower material requirement. 7

8 Thermomechanical rolling Thermomechanical rolling for excellent welding properties We specialize in thermomechanical rolling with accelerated cooling. The thermomechanical rolling process leads to a fine-grained structure that provides high strength, high toughness levels and good cold formability. The very low carbon content and the low carbon equivalent result in excellent welding properties. High toughness in the heat-affected zone (HAZ) and the low susceptibility to cold cracking are critical to highquality weld joints. Benefits of TM steels made by voestalpine High-purity steel (low sulfur, phosphorus and hydrogen content) Very low carbon content and low carbon equivalent Micro-alloys Targeted process and quality assurance during steelmaking, hot rolling and accelerated cooling Processing advantages resulting from the use of TM steels Elimination of or low preheating during welding Reduced manufacturing costs Improved working conditions for the welder Secure weld joints Lower error rates during welding Elimination of stress-relief annealing after welding Welding with high heat input Fewer welding passes Less welding time Lower welding costs Very good cold formability due to fine-grained structure Narrower edging radii than in standard steels Perfect surface Simple surface cleaning as a result of thin and homogeneous layer of scale 8

9 TM-rolled steels have substantially lower carbon content when compared to QT steels and thus have lower cold-cracking potential during welding.

10 Advantages of alform Excellent weldability The excellent weldability of high-strength and ultra-high-strength alform steels is achieved through a combination of thermomechanical rolling and micro-alloying, which makes it possible to achieve very low carbon content. The resulting advantages are as follows: Broad range of welding parameters/wide welding range Low tendency towards age hardening Low tendency toward temper softening in the heat-affected zone Cold cracking resistance without preheating Excellent formability of the heat-affected zone Susceptibility to cold cracking according to Graville, including 960 MPa yield strength 0,25 0,20 Medium susceptibility to cold cracking High susceptibility to cold cracking Carbon content [%] 0,15 0,10 0,05 Low susceptibility to cold cracking TM QT 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 Carbon equivalent CE Graville = C+(Mn+Si)/6+(Cr+Mo+V)/5+(Ni+Cu)/15 [%] Different material grades are characterized by a variety of welding behaviors. Three ranges with different levels of susceptibility to cold cracking are differentiated according to Graville in dependence on carbon content and carbon equivalent. When compared to conventional QT steels, the carbon content is especially low in alform TM steels with minimum yield strengths ranging between 700 and 960 MPa. For this reason, these steel grades do not tend as readily to harden in the heat-affected zone (HAZ) and have low susceptibility to cold cracking. The benefits are achieved by means of a modern analysis strategy, thermomechanical rolling and accelerated cooling. Post-treatment of the weld seam is recommended in order to take advantage of the full potential of weight savings, even in dynamically stressed components. 10

11 A new dimension in welding: alform welding system alform welding system is the world s first custom-matched system of steels and consumables for highstrength and ultra-high-strength welded structures. This opens up an entirely new dimension of our alform steels with respect to material expertise. The base material properties were taken into consideration in the design of the filler metals. In combination with tempering-resistant base materials, property profiles occur in the welded joints that allow substantial extension of the welding ranges. The heat input is tendentially higher and increases the process reliability while lowering manufacturing costs as a result of the increased deposition rate. Exceptional strength The optimized system of tempering-resistant steel grades and adapted filler metals guarantees strength values in the welded joint across a wide range of parameters. These values meet the demands of the respective base materials. Excellent toughness The steel grades and filler metals in the system reliably meet the toughness requirements in the welded joint (heat-affected zone and weld metal). The excellent values guarantee high operating safety at low temperatures under complex loading conditions. Comprehensive advantages Consistently high quality of base materials and welding consumables Pre-tested system solution that guarantees optimum attribute profiles of the component Reduced costs and increased manufacturing reliability through extended welding range Professional application consultation coupled with comprehensive processing expertise 11

12 Advantages of alform Excellent cold formability The homogeneous and fine-grained microstructure lends high-strength and ultra-high-strength steels their decidedly improved forming behavior with more than twice the minimum yield strength than that of conventional structural steels. High-strength and ultra-high-strength alform steels have a significantly smaller bending radius than conventional construction steels. You will find more detailed information on guaranteed minimum radii in the respective alform data sheets. Guaranteed minimum edging radii The smallest permitted inside radius at 90 edging for sheet thickness based on alform 960 x-treme and S960QL Smallest permitted inside radius at 90 edging for sheet thickness s 5 s 4 s 3 s 2 s 1 s Standard S960QL steel alform 960 x-treme Up to 50% smaller edging radii compared to standard steels 3 6 > 6 8 Sheet thickness s [mm] 12

13 Best cuttability High-strength and ultra-high-strength alform steel grades are characterized by their low residual stress. This avoids distortion to a great extent during the cutting process. High-strength and ultra-high-strength alform steels are very well suited to laser and plasma cutting techniques. They are characterized by an extremely uniform surface and homogeneous microstructure across the entire cross-section of the sheet. This is achieved through a thin and uniform scale layer, special alloy design and a high degree of purity with respect to non-metallic inclusions during melting. The sheet production technologies are designed to minimize residual stresses and to avoid distortions during cutting. Significant improvements in the quality of the cut and cutting speed can be achieved by optimizing processes and materials. Perfectly adapted cutting devices and parameters are a prerequisite to utilizing the advantages of the materials. The reduced material thicknesses in applications of high-strength and ultra-high-strength alform steel grades lead to higher cutting speeds and thus to higher throughput rates. Cutting speed Increased laser cutting speed with reduced material thickness 10 8 Cutting speed [m/min] Sheet thickness [mm] 13

14 Advantages of alform Perfect surface A homogeneous layer of scale forms on the sheet surface during thermomechanical rolling and accelerated cooling. This uniform oxide layer is a form of natural protection against corrosion during transport of the product to the customer and makes it unnecessary to apply an environmentally incompatible primer. The rolling scale is thin and can be removed more easily by sandblasting prior to further processing at the customer than the thick mill scale created by the conventional annealing route. This also means less scale accumulation during processing in customer production lines. Less surface scale Comparison between alform and QT sheets 10 mm 10 mm QT sheets Annealing results in a pronounced layer of scale that may leave impressions during leveling. alform sheets The thin layer of scale minimizes the danger of surface damage during further treatment. 14

15 Excellent toughness Thermomechanical rolling and accelerated cooling lead to a finegrain microstructure with excellent toughness in alform steel grades. The alform steel grades with minimum yield strengths of 900 and 960 MPa meet the requirements of notch impact energy in the corresponding QL steel grades according to EN All toughness requirements of EN are met, and higher values than those required in the standard can be met in some steel grades upon request. The excellent toughness of alform plate 700 M is of special interest. This steel grade demonstrates excellent notch impact energy down to very low temperatures. When welded appropriately, high toughness and a very reliable welded joints are achieved in the heat-affected zone (HAZ). Notch impact energy Notch impact energy transition based on alform plate 700 M and S690QL Notch impact energy [J] alform plate 700 M S690QL Test temperature [ C] 15

16 alform in detail Product names alform is a product brand name of the voestalpine Steel Division. High-strength and ultra-high-strength alform steels are available as hot-rolled strip, cut sheets made from hot-rolled steel strip and heavy plate. The names of the individual steel grades include codes for both the minimum yield strength and the manufacturing method, as shown below. Example of product name for alform plate 700 M and alform 960 x-treme alform... voestalpine product brand name plate... classification for heavy plate 700 and minimum yield strength in MPa M... classification for thermomechanically rolled alform steels x-treme... classification for high-strength, thermomechanically rolled alform steels with minimum yield strengths > 900 MPa Comparison with standard steels Hot-rolled steel strip High-strength and ultra-high-strength alform steels up to and including 960 MPa minimum yield strength are supplied based on the following standards: EN : alform 700 M, alform 900/960 x-treme EN : alform 900/960 x-treme When compared to the standards, alform steels demonstrate improved tolerances in several property categories. There is currently no applicable European steel standard for ultra-high-strength steel grades with minimum yield strengths of higher than 960 MPa. Heat treatment up to the following maximum temperatures is possible (i.e. stress-relief annealing up to 30 minutes max.) in thermomechanically rolled alform steels: 580 C: alform 700 M 550 C: alform 900/960/1100 x-treme Higher temperatures lead to a drop in strength. Heavy plates The chemical composition and mechanical characteristics of heavy plate meet the requirements of EN with respect to quenched and tempered steel grades. In addition to the thermomechanically rolled steels and under the brand name aldur, we also offer conventionally quenched high-strength fine-grained steel S690 according to EN The guaranteed notch impact energy is offered in three grade categories: aldur 700 Q (temperature rating of 20 C), aldur 700 QL (temperature rating of 40 C) and aldur 700 QL1 (temperature rating of 60 C). 16

17 Available dimensions The different production routes for cut sheets made of hot-rolled steel strip and heavy plate result in specific product advantages that are described in greater detail in the respective data sheets. Available dimensions Steel grades alform 700 M alform 900 x-treme alform 960 x-treme alform 1100 x-treme Thickness mm Maximum width mm Maximum length mm As-delivered condition 2) Cut sheets made of hot-rolled steel strip 2.0 < 2.5 1, < 3.0 1, < 3.5 1,510 12,000 TM , < 4.0 1, < 7.5 1,620 12,000 TM , < 4.0 1, < 4.5 1, < 7.5 1,620 12,000 TM , , ,430 12,000 TM Heavy plates ,000 alform plate 620 M > ,500 18,700 TM > ,800 1) ,000 18,700 alform plate 700 M > ,500 18,700 > ,800 1) 18,700 TM > ,800 1) 16,000 alform plate 900 M x-treme ,500 16,000 TM alform plate 960 M x-treme ,500 16,000 TM alform plate 1100 M x-treme ,500 16,000 TM aldur 700 Q, 700 QL, 700 QL ,800 13,200 QT 1) maximum width of 3,750 mm for single weights > 15 t 2) TM = thermomechanically rolled; QT = quenched and tempered Minimum width is 900 mm for cut-to-length sheets and 1,500 mm for heavy plate. The maximum weight per sheet is 19.5 tons. Additional dimensions upon request. You will find detailed technical information in the data sheets and Technical Terms of Delivery available on the Internet at and Information and product properties provided in this publication have the sole purpose of giving non-binding technical guidance and by no means replace individual expert advice from our sales and customer service team. Information and product properties provided in this brochure shall not be deemed guaranteed characteristics unless this has been agreed upon individually. Technical changes reserved, errors and misprints excepted. No part of this publication may be reprinted without explicit written permission by voestalpine Stahl GmbH. 17

18 We lead the way, so our partners will be one step ahead. Many years of partnerships with renowned companies impressively prove our point. 18

19 We talk solutions That is why we will never be satisfied with excellent product quality alone. Comprehensive services and unlimited dedication to the challenges of our customers are at the core of our philosophy. Highly specialized and closely linked, the companies of the voestalpine Steel Division have one common goal, which is providing our customers with optimized and individualized packages of benefits. Development advantages Comprehensive material and technology expertise Fast development of custom-designed solutions Technical consulting and support, including application issues In-house research and development center Networking with international research institutions and universities Precisely tailored to your needs Precision cutting for the customized production of high-quality slit strips and cut shapes Short manufacturing times and individualized production planning Comprehensive product selection Individualized and punctual Loyalty to delivery deadlines and online order tracking Tailored logistics and just-in-time delivery Customized packaging Always close to you Expert contacts directly on site Sales offices in more than 20 countries A strong partnership Close collaboration with our Group companies in order to create unique expertise and the technological leadership of our products You will also find further voestalpine product information at voestalpine Böhler Welding ( 19

20 01/14 Technically more advanced. Successful together. voestalpine Steel Division the partner you can trust. High-quality materials are the basis for our products. We strive to be the best partner for our customers and want to provide them with the best-possible solutions. We focus our expertise on two aspects: The personal aspect, with dedicated and highly competent employees The technical aspect, with high-quality methods, products and services The companies in the voestalpine Steel Division and their employees understand partnership to be the following: Understanding for their customers business Expertise and reliability Responsibility for satisfactory project completion Partnerships based on trust Many years of successful partnerships with our customers prove our point. voestalpine Steel Division voestalpine-straße Linz, Austria T. +43/50304/ mechanical.engineering@voestalpine.com