BRIGHT HEAT TREATMENT OF FLAT AND PROFILED WIRE MADE OF AUSTENITIC AND FERRITIC STAINLESS STEELS

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1 Global Ferrous Rod & Wire Symposium (Interwire 2017) Atlanta, May 2017 BRIGHT HEAT TREATMENT OF FLAT AND PROFILED WIRE MADE OF AUSTENITIC AND FERRITIC STAINLESS STEELS Authors: Igor Rogelj, Primoz Eiselt, Franz Resch, Plasmait GmbH, Austria Willy Hauer, Howar Equipment Inc. Plasmait: Tel (Austria): ; Tel (International): Howar Equipment: Tel: ; Fax: April 17 1

2 Agenda Overview of traditional annealing processes for stainless steels PlasmaANNEALER key components and typical line configuration Example of PlasmaANNEALER: HPA30-2S with tempering zone for austenitic, martensitic, ferritic and duplex stainless steels MATERIAL APPLICATION EXAMPLES: Austenitic Stainless SUS 304: 30mm x 3mm & Φ 6.0mm Ferritic Stainless SUS 430: 9mm x 0.5mm & 30mm x 3mm Spring Steel SAE 9254 V: Φ 2.7mm Martensitic Stainless SUS 420C: Φ 2.4mm Duplex Stainless LDX2101: Φ 6mm Comparing plasma annealing with traditional annealing processes April 17 2

3 Traditional Annealing Processes for Stainless Steels Strand Annealing Furnace Continuous process / low speed / multiline Quick temperature profile manipulation and quenching possible Long-term tempering/annealing NOT possible Induction Annealer Continuous process / high speed / single line Quick temperature profile possibilities and quenching possible Long-term tempering/annealing NOT possible Batch Annealing Furnace Batch process / high output / long tempering/annealing times possible Slow temperature profile manipulation April 17 3

4 Components of PlasmaANNEALER Vacuum System / Gas Supply Material Guiding and material supports Plasma Module: cleaning & heating Tempering Module : slow cooling zone Cooling: Hydrogen recirculation in water jacket optional: direct water cooling for T < 400ºC PLC Controls with HMI Plant frame Heating Module Tempering Module Slow cooling zone H2 Cooling Section PLC & HMI Rapid Heating OPTIONAL: Tempering, slow cooling Hydrogen recirculation cooling with secondary water cooling (water jacket) OPTIONAL EXTRA: Direct water cooling for material < 400ºC April 17 4

5 Components of PlasmaANNEALER Vacuum System / Gas Supply Material Guiding and material supports Plasma Module: cleaning & heating Tempering Module / slow cooling zone Cooling: Hydrogen recirculation in water jacket optional: direct water cooling for T < 400ºC PLC Controls with HMI Plant frame Wire Guides / Sealing with Vacuum System Supports for hot material HEAT TREATMENT: Low pressure (vacuum) COOLING: Over-pressure & gas recirculation April 17 5

6 PlasmaANNEALER Example: HPA30-2S High-speed annealing of stainless grades: austenitic, ferritic, martensitic Can Includes tempering zone for grades that require tempering / slow cooling Material size range: round up to 20 mm flat up to 20mm x 3mm Output: max 150kg/h, subject to material grade April 17 6

7 Heat Treatment HPA30-2S Heating Module: Tempering Module: 610mm 1250mm Typical tempering lengths: 1m - 5m, as necessary for application April 17 7

8 Gas and Cooling HPA30-2S Purging gas options: a) Hydrogen b) Forming gas (slower cooling longer cooling necessary) Cooling system: Gas recirculation + secondary water cool (water jacket) Optional extra: direct water cool at the end of cooling section for cooling of material at temperatures below 400ºC April 17 8

9 User Interface (HMI) Main screen Technologist/supervisor sets production recipes into the recipe database as part of commissioning, new product development process Operator selects production recipe from list for different applications Operator has limited access/manipulation rights as defined by supervisor/manager Home screen provides key process data. Operator can manipulate only speed and power correction within a preset range. Parameters for each unit are manipulated on separate screens Key process parameters are on the edge of the screen April 17 9

10 User Interface (HMI) Recipe screen April 17 10

11 User Interface (HMI) Plasma screen April 17 11

12 User Interface (HMI) Cooling screen April 17 12

13 PlasmaANNEALER for Stainless Steel Machine Options: HPA10 / HPA20 / HPA40 / HPA60 / HPA80 Annealing output on Austenitic stainless steels: max 4.5kg/h per 1kW HPA10 (max 10kW): max 45kg/h HPA80 (max 80kW): max 360kg/h Annealing output on Ferritic stainless steels (without tempering): max 6.25kg/h per 1kW HPA10 (max 10kW): max 62kg/h HPA80 (max 80kW): max 500kg/h Outputs for tempered materials are lower as above, subject to application April 17 13

14 PlasmaANNEALER: Example Performance Table Table of output, power consumption and finished mechanical properties for selected applications Material Grade Size Annealer Output Power Usage Mechanical Properties Heat Treatment Notes Austenitic Stainless SUS 304 Φ 6mm HPA80-3S 360 kg/h 300 kwh/ton A (elongation) = 45%-60% Rm (UTS) = MPa Rapid heating to 1100 C > rapid gas cool Austenitic Stainless SUS mm x 3mm HPA40-2S 150 kg/h 400 kwh/ton A (elongation) = 45%-55% Rm (UTS) = MPa Rapid heating to 1100 C > rapid gas cool Ferritic Stainless SUS 430 Ferritic Stainless SUS 430 Martensitic Stainless SUS 420C Spring Steel SAE 9254 V Duplex Stainless LDX mm x 3mm HPA30-2S 100 kg/h 500 kwh/ton 9mm x 0.5mm HPA30-2S 64 kg/h 550 kwh/ton Φ 2.4mm HPA40-2S 195 kg/h 310 kwh/ton Φ 2.7mm HPA30-2S 82 kg/h 340 kwh/ton Φ 6mm HPA40-2S 150 kg/h 380 kwh/ton A (elongation) > 18% Rm (UTS) < 500 MPa A (elongation) > 16% Rm (UTS) < 540 Mpa A (elongation) > 24% Rm (UTS) < 720 MPa A (elongation) > 12% Rm (UTS) < 1000 MPa A (elongation) > 30% Rm (UTS) = MPa Heating to 800 C-850 C > slow cool to 600 C > hold > rapid gas cool Heating to 800 C-850 C > slow cool to 600 C & hold > rapid gas cool Heating to approx. 800 C > gas cool Heating to approx. 650 C > slow cool to 600 C & hold > gas cool Rapid heating over 1050 C > hold > rapid gas cool April 17 14

15 PlasmaANNEALER Quantitative Process Comparison Strand Furnace Induction Annealer Plasma Annealer Process type Multi-line / low-speed Single line / high-speed Single line / highspeed Energy cost / kg of output High Low (steel) High (stainless) Purging gas cost High High Low Labour cost High Low Low Maintenance cost High Low Low Low Production uptime Low if different T req. High if constant T req. Low if different sizes req. High if one size req. Subject to impedance matching High Irrespective of material size and T range Production line footprint Large Compact Compact Capex furnace Low High High Capex payoffs and takeups Working capital locked in material Annealing power control/ temperature control Recrystallization uniformity (stainless) High Low Low High Low Low Limited / Slow Poor for non-magnetic mat. Accurate and immediate High Low High Surface quality Poor Subject to setup High Note: the quantitative comparison above is for indication only and does not apply correctly in all 15 applications April 17 and all manufacturing setups. Please contact the authors to discuss specific application.

16 Global Ferrous Rod & Wire Symposium (Interwire 2017) Atlanta, May 2017 BRIGHT HEAT TREATMENT OF FLAT AND PROFILED WIRE MADE OF AUSTENITIC AND FERRITIC STAINLESS STEELS Authors: Igor Rogelj, Primoz Eiselt, Franz Resch, Plasmait GmbH, Austria Willy Hauer, Howar Equipment Inc. Plasmait: Tel (Austria): ; Tel (International): Howar Equipment: Tel: ; Fax: April 17 16