Tools & FormingMember ofFrank-Stronach-InstitutePress Hardening of boron steel sheetsIntroduction and Outlook 硼钢板料热成形介绍及展望Univ.-Prof. Dr.-Ing. Ralf KolleckInstitute Tools & FormingMaterials are essential to the forming process 材料对成形工艺非常重要 Increase in part complexity, plus high strength level at sufficient breaking at fracture零件复杂度的增加，另外需要在充分破坏和断裂时有高强度水平Highest tool requirements最高模具要求Application of UHSS: The sheet is retting the tool“应用超高强度钢时：“板 料时刻磨耗模具”Image source: FordImage source: VolkswagenLimited shaping possibilities形状受限Use of new materials (ultra) high strength steel (UHSS),Early failure during drawing process使用新型超高强钢（UHSS），在拉深过程中产生早期失效Increased safetydemands/ lightconstruction增加了 安全要求/结构轻2Institute Tools & FormingDirect press hardening of boron alloyed steels 硼合金钢直接热成形通道桥支架后纵梁Press hardeningsatisfies allrequirementsconcerning present-day“ body making热成形能够满足“当前”车身制造所有涉及到的所 有要求B柱通道加固 Manufacturing of complex partgeometries with (ultra)high strenghproperties使用（超）高强属性 纵梁加固Source: Audi 制造复杂几何形状零件资料-奥迪Process steps of direct press hardening:直接热成形工艺步骤 Sheet heating to austenitizing temperature (1173 1223 K)板料加热到奥氏体化温度 Fast on-load forming (vp= 200 - 500 mm/s)快速入模成形 “Hardening” in closed tool (cooling rate min. 27 K/s)在闭合模具中淬火（冷却速度最小27 开/秒)3Institute Tools & FormingPress hardening ofboron alloyed steels硼合金钢热成形4Institute Tools & FormingPress hardening ofboron alloyed steels硼合金钢热成形5Institute Tools & FormingInfluencing variables duringpress hardening 热成形过程的影响变量6Institute Tools & FormingInfluencing variables duringpress hardening 热成形过程的影响变量7Institute Tools & FormingHeating characteristics of a conventional rolling hearth furnace传统辊底式炉的加热特点1273T KT approx.2.7 K/sT approx.1.5 K/s1073973873773Sheet material板材:22MnB5Al/Si coated铝硅镀层t = 1.5 mm673573473Influencing factor:影响因素 Furnace temperature炉温 Sheet thickness板材厚度 Coating thickness镀层厚度 Emission coefficient 辐射系数T Furnace炉温T Sheet板料温37327360 120 t s 2408Institute Tools & FormingHeating technologies加热技术Motivation:推动力 Increased output增加产量 Reduction of investment costs减少投资费用 Reduction of energy consumption per heated semi-finished part 减少个加热半成品零件的能源消耗 Reduction of required space减少占地 Increased flexibility regarding product range增加相应产品范围灵活性Reference参考 Available technologies可用技术Conventional serialproduction传统系列生产Roller hearth furnaceor walking beamfurnace辊底式加热炉或进式加热炉Conduction传导 Induction感应Volkswagen9Institute Tools & FormingPrototype原型: Two steps induction furnace两感应加热炉Surface inductor 表面感应器+150 - 200 KStep 1骤1 Step 2 骤2Longitudinal field inductor 纵向磁场感应器993 1018 K*depending on the thin sheet material依靠薄板料10Institute Tools & FormingProcess window austenitization制程窗口 奥氏体化Surfaceinductor表面感应器Sample material:材料样例22MnB5 uncoated200 x 300 mm, t = 1,5 mmLongitudinalfieldinductor纵向磁场感应器Process steps:过程步骤Heating to 加热到1223 KDuration of heating经历时间35 - 60 sQuenching in water水中淬火Time Comparison比较Inductive感应式Dwell time 滞留30 sConventional传统Dwell time滞留 3min11Institute Tools & FormingComparison of the heating technologies加热技术对比 Conventionalroller hearth furnace 传统辊底式加热炉100 % Required space所需空间Investment costs投资费用 100 %Energy efficiency能源效率53 %Induction furnace感应式加热炉Required space所需空间20 %Investment costs投资费用50 % Energy efficiency能源效率68 %12Institute Tools & FormingInfluencing variables duringpress hardening 热成形过程的影响变量13Institute Tools & FormingTooling technologies模具技术Requirements:要求 In order to guarantee a complete martensite formation: Cooling rate at least 27 K/s 为了能保证完整的马氏体形成：冷却率至少27 K/s Homogeneous temperature distribution constant component properties均匀温度分布恒定的零件属性 Long tool-life (dimensional accuracy, cracks)模具寿命长（尺寸精度，开裂） Predetermined cycle time预先决定的循环时间Reference参考 Specification说明Shell or segmentedconstruction壳式或分段构造 Water cooling水冷 Closure time (8-15 s)闭合时间（8-15秒） Tool material: heat resistance steel e.g. 1. 2343模具材料：耐热钢，例：1.2343 Extensive chipping大范围修整 Production related restrictions Compromise on cooling channelgeometry生产相关限制冷却通道几何形状让步 Impermeability不14Institute Tools & FormingTooling technologies模具技术Motivation:推动力 Reduction of cycle times减少循环时间 Reduction of investments减少投资 Increase of tool-life增加模具寿命 Enhancement of process limitations (partial press hardening, small structures)加强工艺限制（部分淬火，小结构）Design/ Simulation设计/模拟Reference参考 ApproachesShell or segmentedconstruction 壳式或分段构造Tooling material and semi finished component模具材料和半成品零件15Institute Tools & FormingDesign of cooled tools冷却模具设计Componentgeometry零件几何形态Feasibility analysis可行性分析 Gi