Uddeholm Caldie® Uddeholm Caldie
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PRELIMINARY BROCHURE Uddeholm Caldie® Uddeholm Caldie © UDDEHOLMS AB No part of this publication may be reproduced or transmitted for commercial purposes without permission of the copyright holder. This information is based on our present state of knowledge and is intended to provide general notes on our products and their uses. It should not therefore be construed as a warranty of specific properties of the products described or a warranty for fitness for a particular purpose. Classified according to EU Directive 1999/45/EC For further information see our “Material Safety Data Sheets”. Edition 14, revised 09.2016, not printed 2 Uddeholm Caldie Uddeholm Caldie® CHANGING TOOLING ENVIRONMENT New and more demanding work materials are continuously imple- mented in the industry. As a consequence of the introduction of AHSS, Advanced High Strength Steel, the forming tools have to resist higher stress levels and withstand more adhesive and abrasive wear. Many times the tool has to be coated in order to fulfil production require- ments, i.e. the tool material also has to be a good substrate material for different type of surface coatings. THE PROBLEM SOLVER Uddeholm Caldie is the first ESR-grade and developed with main focus on severe cold work applications. The excellent combination of compressive strength, wear resistance and chipping/cracking resistance has been achieved by a well bal- anced chemistry of matrix type and a clean and homogeneous micro- structure. Appropriate heat treatment properties and high fatigue strength make Uddeholm Caldie also to a perfect substrate material for surface coatings A VERSATILE TOOL STEEL The unique properties profile of Uddeholm Caldie include very good weldability, castability, through hardening properties, machinability and grindability. This means that Uddeholm Caldie provides many different options for eco-nomical toolmaking, tool using and maintenance, especially for larger forming tools. 3 Uddeholm Caldie GENERAL • Thread rolling dies • Substrate for surface coatings Uddeholm Caldie is a chromium-molybdenum- vanadium alloyed tool steel which is charac- UDDEHOLM COMPONENT BUSINESS terized by: APPLICATIONS • very good chipping and cracking resistance Uddeholm Caldie can be used in engineering • good wear resistance applications where high compressive strength • high hardness (>60 HRC) after high tem- has to be combined with high ductility/ perature tempering toughness. Knives for fragmentation of • good dimensional stability in heat treatment plastics and metals and roll forming rolls are and in service good examples. • excellent through-hardening properties • good machinability and grindability • excellent polishability • good surface treatment properties PROPERTIES • good resistance to tempering back The properties below are representative of • very good WEDM properties samples which have been taken from the centre of bars with dimensions 203 x 80 mm Typical C Si Mn Cr Mo V and Ø 102 mm. Unless otherwise indicated, all analysis % 0.7 0.2 0.5 5.0 2.3 0.5 specimens have been hardened at 1025°C Standard (1875°C), gas quenched in a vacuum furnace specification None and tempered twice at 525°C (975°F) for two Delivery hours to 60–61 HRC. condition Soft annealed to max. 215 HB Colour code White/grey PHYSICAL PROPERTIES Hardened and tempered to 60–61 HRC. Temperature 20°C 200°C 400°C APPLICATIONS (68°F) (390°F) (750°F) Uddeholm Caldie is suitable for short to Density, medium run tooling where chipping and/or kg/m3 7 820 – – lbs/in3 0.282 cracking are the predominant failure mecha- Modulus of elasticity nisms and where a high compressive strength MPa 213 000 192 000 180 000 (hardness above 60 HRC) is necessary. This psi 31.2 x 106 27.8 x 106 26.1 x 106 makes Uddeholm Caldie an excellent problem Coefficient of solver for severe cold work applications where thermal expansion per °C from 20°C–11.6 x 10–6 12.4 x 10–6 the combination of a hardness above 60 HRC per °F from 68°F– 6.4 x 10–6 6.9 x 10–6 and a high cracking resistance is of utmost Thermal importance e.g. as in the blanking and forming conductivity of ultra high strength steel sheets. W/m °C – 24 28 Btu in/(ft2h°F) – 174 195 Uddeholm Caldie is also very suitable as a substrate steel for applications where surface Specific heat J/kg°C 460 – – coatings are desirable or necessary. Btu/lb°F 0.11 COLD WORK APPLICATIONS • Blanking applications where high ductility COMPRESSIVE STRENGTH and toughness are needed to prevent chipping/cracking Approximately compressive strength vs. hardness is shown in the table below. • Cold forging and forming operations where a high compressive strength combined with Hardness Compressive yield strength, good resistance to chipping/cracking are HRC Rc0,2 (MPa) necessary 58 2230 60 2350 • Machine knives 61 2430 4 Uddeholm Caldie CHIPPING RESISTANCE STRESS RELIEVING Relative chipping resistance for Uddeholm After rough machining the residual stresses Caldie, AISI A2 and AISI D2 is shown below. should be relieved by tempering at 650°C (1200°F), holding time 2 hours. Cool slowly in 5 the furnace to 500°C (930°F), then freely in air to room temperature. 4 HARDENING 3 Preheating temperature: 600–650°C (1110– 1200°F) and 850–900°C (1560–1650°F). In 2 case of bigger dimensions (>150 mm cross section) a third preheating step at 930°C (1700°F) is recommended. 1 Austenitizing temperature: 1000–1050°C Caldie AISI A2 AISI D2 (1830–1920°F), normally 1020°C (1870°F), in case of bigger dimensions (>150 mm cross section) 1000°C (1830°F). HEAT TREATMENT Holding time: 30 minutes after the tool is heated through. SOFT ANNEALING Note: Holding time = time at hardening tem- Protect the steel and heat through to 820°C perature after the tool is fully heated through. (1510°F wait for equalization of the tempera- A holding time of less than recommended time ture (equalization time related to the size of the will result in loss of hardness. tool). Then cool in the furnace at 10 C (20 F) ° ° The tool should be protected against decarbu- per hour to 650°C (1200°F), then freely in air to rization and oxidation during hardening. room temperature. Further information can be found in the Uddeholm brochure “Heat treatment of tool steels”. CCT-GRAPH Austenitizing temperature 1025°C (1880°F). Holding time 30 mintues. °F °C 2000 1100 Austenitizing tem. 1025°C (1880°F) Holding time 30 minutes 1800 1000 900 1600 Ac = 870°C (1600°F) 1f Ac = 805°C (1480°F) 800 1s 1400 Carbides Pearlite 700 Cooling T Curve Hardness 800–50 1200 No. HV 10 (sec) 600 1 824 2 1000 500 2 813 140 800 3 803 280 400 Bainite 4 803 1030 600 300 5 792 1596 400 200 6 690 2325 Ms 525 200 100 7 5215 1 2 3 4 5 6 7 8 Martensite 8 464 13850 1 10 100 1 000 10 000 100 000 Seconds 1 10 100 1 000 Minutes 1 10 100 Hours 0.2 1.5 10 90 600 Air cooling of bars, Ø mm 5 Uddeholm Caldie QUENCHING MEDIA ductility, a minimum temperature of 540°C (1000°F) and three tempers is strongly recom- •Vacuum (high speed gas with sufficient mended. overpressure minimum 2 bar) Tempering at a lower temperature than • Martempering bath or fluidized bed at 540°C (1000°F) may increase the hardness approx. 200–550°C (390–1020°F) and compressive strength to some extent but • Forced air/gas also impair cracking resistance and dimen- Note: Temper the tool as soon as its tempera- sional stability. However, if lowering the tempering temperature, do not temper below ture reaches 50–70°C (120–160°F). In order to obtain the optimum properties for 520°C (970°F). When tempering twice the the tool, the cooling rate should be as fast as minimum holding time at temperature is possible with regards to acceptable distortion. 2 hours. When tempering three times the A slow quench rate will result in loss of minimum holding time is 1 hour. hardness compared with the given tempering curves. TEMPERING TABLE Martempering should be followed by forced air cooling if wall thickness is exceeding Hardening Tempering temperature temp. 540°C 550°C 560°C 50 mm (2”). 1000°C* (1830°F*) 57–59 HRC 56–58 HRC 54–56 HRC TEMPERING 1020°C (1870°F) 58–60 HRC 57–59 HRC 55–57 HRC Choose the tempering temperature according 1050°C to the hardness required by reference to the (1920°F) 59–61 HRC 58–60 HRC 56–58 HRC tempering graph below. Temper at least twice with intermediate cooling to room tempera- For high dimensional stability min. 540°C (1000°F) and 3 x 1 h should be used. ture. For highest dimensional stability and *Hardening temp. 1000°C (1830°F) should be used for cross sections >150 mm (6" thick). TEMPERING GRAPH Hardness, HRC Retained austenite % 64 40 Austenitizing temperature 35 60 1050°C (1920°F) Austenitizing 30 56 Retained austenite 1050°C (1920°F) temperature 1020 C (1870 F) ° ° 25 52 20 Retained austenite 1020°C (1870°F) 48 15 10 44 5 40 200 300 400 500 600 °C 390 570 750 930 1110 °F Tempering temperature The tempering curves are obtained after heat treatment of samples with a size of 15 x 15 x 40 mm, cooling in forced air (T800–500 = 300 sec.). Lower hardness can be expected after heat treatment of tools and dies due to factors like actual tool size and heat treatment parameters. 6 Uddeholm Caldie HARDNESS, GRAIN SIZE AND SURFACE RETAINED AUSTENITE AS A FUNCTION OF AUSTENITIZING TEMPERATURE TREATMENTS Grain size Tool steel may be given a surface treatment ASTM Retained austenite % in order to reduce friction and increase wear 10 Hardness, HRC 66 50 resistance.