Ferritic Nitrocarburizing (Fnc) Processes & Applications

Ferritic Nitrocarburizing (Fnc) Processes & Applications

FERRITIC NITROCARBURIZING (FNC) PROCESSES & APPLICATIONS Benjamin T. Bernard Surface Combustion, Inc. OUTLINE AGENDA • FNC Metallurgy • Metalúrgico FNC • Atmosphere • Atmósferas • Furnace Equipment • Hornos • Process Control / Standards • Control del Proceso • Conclusions • Normas • Conclusiones Ferritic FERRÍTICO • Ferritic implies temperatures less • Ferrítico significa temperaturas de baja than the A1 line (1400°F(760°C)) in temperatura, menos de la temperatura cuando la transformación metalúrgico the iron-carbon phase diagram a austenita se ocurre (A1) (760°C ‒ No BCC to FCC transition (1400°F)) hierro-carbon diagrama fase. ‒ Solubility of N in Steel is ‒ No BCC a FCC limiting factor during FNC, ‒ Solubilidad de nitrógeno en acero lower temperatures es el limite en el proceso FNC, baja temperaturas • Available nitrogen from ammonia • Nitrogeno es disponible desde de- dissociation enlace de amoniaco ‒ NH3 N(g) + 3/2(H2) ‒ NH3 N(g) + 3/2(H2) 3/2 3/2 ‒ Kn = pNH3/p(H2) ‒ Kn = pNH3/p(H2) • Nitrogen Diffuses Into The • Nitrogeno se difusa a acero Steel • Nitrogeno se combina con • Nitrogen Reacts With The elementos de aleación que puede Nitride-Forming Elements formar nitruro • Endurezca de superficie • Hardening Results From This NITRIDE FORMING ELEMENTS Stange Elektronik ECS • Chrome (Cr), Aluminum (Al), Iron (Fe) • Fe3N (Epsilon) • Fe4N (Gamma Prime) • As alloying increases, the Nitrogen diffusion zone decreases ELEMENTOS QUE SE PUEDE NITRURAR • Cromo (Cr), Aluminio (Al), Hierro (Fe) • Fe3N (Epsilon) • Fe4N (Gamma Prime) • Cuando se aumenta la nivel de aleación, la profundidad de difusión de nitrógeno va a bajar FNC METALLURGY • Carbon Steel ‒ Typical Specification . WHITE LAYER = 0.0005 (12.7 μm) A. 50X mag. Metalúrgico FNC • Acero de Bajo Carbon ‒ Especificacion . Capa Blanca = 0.0005 (12.7 μm) B. 200X mag. (White Layer = 13-18 microns HV = 500) FNC METALLURGY • Ductile Iron ‒ Ammonia / RX® Gas ‒ WHITE LAYER = . 0.0006” avg. (15.2 μm) ‒ Ammonia / N2/ CH4 ‒ WHITE LAYER = . 0.0006” (15µm) A. 200X mag. Metalúrgico FNC • Hierro Fundición Dúctil (Ductile Iron) ‒ Amoniaco / RX® Gas Endotérmico ‒ CAPA BLANCA = . 0.0006” (15.2 μm) ‒ Amoniaco / N2/ CH4 ‒ CAPA BLANCA = . 0.0006” (15µm) B. 500X mag. FNC ADVANTAGES VENTAJAS FNC • Increase in Surface • Endurezca de superficie Hardness • Resistente a desgaste y • Increase Wear Resistance & corrosión Anti-Galling Properties • Menos Distorsión por el • Low Part Distortion Due to proceso a baja Low Operating temperatura 700°F Temperatures 700°F (370°C) to 1100°F (370°C) to 1100°F (593°C) (593°C) • Improved Part Lubricity • Mejor lubricidad del parte FNC ADVANTAGES • Improved Corrosion Resistance • Improved Fatigue Life VENTAJAS FNC • Resistencia a corrosión • Resistencia a la fatiga Ref: CHTE NitrideTool® FNC ATMOSPHERE • Ammonia (NH3) based with myriad of available carrier gases and diluents ® • RX Endothermic Gas and NH3 ® • RX with dissociated NH3 and N2(g) ® • DX Exothermic Gas and NH3 ATMOSFERA FNC • Amoniaco (NH3) con gases corregidos y gases diluyentes ® • RX Gas Endotérmico y NH3 ® • RX con NH3 (desasociado) y N2(g) ® • DX Gas Exotérmico y NH3 TYPICAL ATMOSPHERES & PROCESS ATMOSFERAS & PROCESOS TIPICOS • Pre-Oxidize / Pre-Heat • Pre-Oxidación / Pre-Calentar • Purge In With Nitrogen • Purga con Nitrógeno • Introduce Process Gasses • Introduce Gases del Proceso • Purge Out / Process Cool • Purga al final / Enfriar • Post Oxidize, If Required • Post Oxidación RX® ATMOSPHERE GENERATION • Provides N2, CO, H2 • Additional Gases Needed for FNC: ‒ NH3 ‒ N2(g) ‒ CH4 • LEL of RX® is 1400°F, so care should be taken to operate at FNC temperatures RX® ATMOSFERA • Producir N2, CO, H2 • Otras atmósferas para FNC: ‒ NH3 ‒ N2(g) ‒ CH4 • Mínimo Temperatura de Explosion (LEL) de RX® es 1400°F (760°C), sistemas de seguridad deben que esta instaladas ATMOSPHERES Atmosphere Varieties For Cast Iron: A. 40% Endothermic, 60% Ammonia B. 35% Nitrogen, 5% Methane, 60% Ammonia C. 40% Ammonia, 55% Nitrogen, 5% Carbon Dioxide ATMOSFERAS Hierro Fundido: A. 40% Endotérmico, 60% Amoniaco B. 35% Nitrógeno, 5% Metano, 60% Amoniaco 200X mag. C. 40% Amoniaco, 55% 2-3 Horas Nitrógeno, 5% Gas Carbónico Temperatura 1050°F NITRIDE (PROCESS GAS) TRADENAMES • TrinidingTM ‒ 1050°F, 4 hrs., NH3, N2(g) and CH4 ‒ Epsilon or Gamma prime • Lindure® ® • 900-1100F, 2hrs., RX and NH3 • Epsilon • Nitroflex® − 1050-1100°F, 1-5 hrs., NH3, CO2, N2 − N2 + N2O for blackening − Epsilon with deep diffusion layer covered with black oxide PROCESOS de NITRUAR con MARCAS REGISTRADAS • TrinidingTM Triniding is a trademark of Surface Combustion ‒ 1050°F (566°C), 4 hrs., NH3, N2(g), y CH4 Lindure is a registered trademark of Bodycote ‒ Epsilon o Gamma prime Nitroflex is a registered trademark of Linde • Lindure® ® • 900-1100F (482-593°C), 2hrs., RX y NH3 • Epsilon • Nitroflex® − 1050-1100°F (566-593°C), 1-5 hrs., NH3, CO2, N2 − N2 + N2O para oxido negro − Epsilon con difusión profundo y superficie de oxido negro FNC PRE-PROCESS CONSIDERATIONS • Hardened/Tempered • Stress Relieve − T should be less than FNC temperature • Thoroughly Cleaned • Optional − Pre-oxidize (N2O or H2O) − Shot Blast − Machine − Phosphate Coat − Acid Etch (Activation) PROCESOS ANTES de FNC • Endurecer y Revenir • Eliminación de Esfuerzos − Temperatura debe estar menos que el proceso de FNC • Piezas limpias • Opcional − Pre-oxido (N2O or H2O) − Chorreo con granalla − Maquinado − Fosfatacion − Atacar con acido (Activación) FURNACE DESIGNS FOR FNC DISEÑOS DE HORNOS PARA FNC • Batch Integral Quench Furnaces - Hornos de temple integrales • FNC Furnaces - Hornos FNC • Pit Furnaces - Hornos tipo Foso • Cover & Base Furnaces - Hornos tipo Campana • Horizontal Retort Furnaces - Hornos Horizontales con Retortas • Vacuum Furnaces - Hornos de Vacio • Continuous Furnaces - Hornos Continuos • Companion Equipment - Equipamiento Auxiliares • Ion Furnaces – Hornos Ionico ALLCASE® BATCH INTEGRAL QUENCH FURNACES Typical Furnace For Gaseous FNC With Both An Oil Quench And Atmospheres Quench Hornos ALLCASE® Horno Allcase tipico para FNC con temple de aceite y RX® lento tambien. BATCH INTEGRAL QUENCH FURNACES PROCESSES: • FNC • Post Oxidation • Carbonitriding • Carburizing ADVANTAGES: • High Productivity On Short Process Cycles (3-4 hours) • Automated Load/Unload • Also Designed For High Temperature Processes • Oil/Polymer Quench Ability • Atmosphere (N2 or RX®) cooling with Top Cool • Slow Ammonia Dissociation Hornos con Temple Integrales PROCESOS: • FNC • Post Oxido • Carbonitrurar DISADVANTAGES: • Carburar • Not Recommended For Classical Gas Nitriding Because Of No Retort (refractory VENTAJAS: • Producción mayor con ciclos cortos (3-4 hrs) lined) • Cargar/ Descargar Automático • Flexibilidad a Procesar hasta 2000F (1093C) DESVENTAJAS: • Temple de Aceite o Polímero • No tiene retorta (aislado con ladrillos) por • Temple con Atmósfera (N2 or RX®) en cámara eso no es recomendaría a nitruar Top Cool solamente, debe procesar con carbon (FNC) • Taza lenta disociar Amoniaco BIQ TEMPERATURE UNIFORMITY - FNC Uniformidad Temperatura Horno Integral - FNC 1100 1080 1060 1040 1020 TC#1 1000 TC #2 TC #3 980 TC #4 Temperature (°F) 960 TC #5 940 TC #6 920 TC #7 900 TC #8 TC #9 9:54:319:56:019:57:319:59:01 10:00:3110:02:0110:03:3110:05:0110:06:3110:08:0110:09:3110:11:0110:12:3110:14:0110:15:31 FNC UNIFORMITY Uniformidad BATCH FURNACE Horno Integral - FNC FNC UNIFORMITY FNC Calidad – Horno Batch BATCH FURNACE FNC UNIFORMITY FNC Calidad – Horno Batch BATCH FURNACE FNC UNIFORMITY BATCH FURNACE FNC Calidad – Horno Batch FNC QUENCH FURNACES PROCESSES: • FNC • Atmosphere Tempering ADVANTAGES: • Optimized Design for Low Temperature FNC Process ‒ Smaller Footprint • Less Volume for Heating / Process Gases • High Productivity On Short Process Cycles • Automated Load/Unload • Top Cool Option Available FNC Horno Temple PROCESOS: • FNC • Revenir en atmósfera protectiva DISADVANTAGES: VENTAJAS: High temperature (>1250°F (677°C)) processes • Diseño especifico para proceso FNC a temperaturas cannot be done in this furnace bajas ‒ Menos espacio en fabrica DESVENTAJAS: • Menos volumen para calentar y gas del proceso • Producción mayor con ciclos cortos No se puede procesar >1250°F (677°C) • Cargar/ Descargar Automático • Opción Top Cool Low Temperature FNC Furnace FNC Horno Temple TIME TEMPERATURE CURVE Tiempo v. Temperatura Process Value Working SetPoint Output % 1150 100 1130 90 1110 80 1090 70 1070 60 1050 50 1030 40 Output (%) Output Temperature (°F) Temperature 1010 30 990 20 970 10 950 0 0:00:000:01:200:02:400:04:000:05:200:06:400:08:000:09:200:10:400:11:500:20:300:21:500:23:100:24:300:25:500:27:100:28:300:29:500:31:100:32:300:33:50 Time (HH:MM:SS) PIT FURNACE (WITH RETORT ASSEMBLY) PROCESSES: • Nitriding • Nitro-Carburizing • Oxynitriding • Pre-Oxidation • Post Oxidation (Bluing & Blackening) ADVANTAGES: • Custom Sizes Available • Retort & Load Can Be Removed From Heating System To Improve Productivity HORNO DE FOSO (CON RETORTA) PROCESOS: • DISADVANTAGES: Nitrurar • Atmosphere Piping Must Be Disconnected During • NITROCARBURACION Load/Unload • Oxy-nitrurar • Not Productive For Short Cycle Processes • Pre-Oxido • Slower Cooling by External Coolers Compared to • Post Oxido (Bluing & Blackening) Oil Quench VENTAJAS: DESVENTAJAS: • Tómanos a especificación • La tubería de atmósfera debe ser • Retorta y Carga se pueden quitar para desconectados cuando remover la retorta aumentar la productividad • No recomendado para procesos tiempo cortos • Enfriamiento por soplador externo PIT FURNACE HORNO DE FOSO TIME TEMPERATURE

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