CN113151743B - 一种低马氏体含量免调质冷镦钢盘条的制造方法及其应用 - Google Patents
一种低马氏体含量免调质冷镦钢盘条的制造方法及其应用 Download PDFInfo
- Publication number
- CN113151743B CN113151743B CN202110424196.7A CN202110424196A CN113151743B CN 113151743 B CN113151743 B CN 113151743B CN 202110424196 A CN202110424196 A CN 202110424196A CN 113151743 B CN113151743 B CN 113151743B
- Authority
- CN
- China
- Prior art keywords
- wire rod
- cold heading
- equal
- steel wire
- less
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 60
- 239000010959 steel Substances 0.000 title claims abstract description 60
- 229910000734 martensite Inorganic materials 0.000 title claims abstract description 28
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 16
- 238000005496 tempering Methods 0.000 title claims description 9
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 16
- 238000010622 cold drawing Methods 0.000 claims abstract description 13
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 12
- 239000000126 substance Substances 0.000 claims abstract description 12
- 238000010438 heat treatment Methods 0.000 claims abstract description 10
- 238000005728 strengthening Methods 0.000 claims abstract description 9
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 8
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 7
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 6
- 229910052802 copper Inorganic materials 0.000 claims abstract description 5
- 238000000034 method Methods 0.000 claims description 38
- 238000001816 cooling Methods 0.000 claims description 33
- 238000005096 rolling process Methods 0.000 claims description 21
- 238000009749 continuous casting Methods 0.000 claims description 17
- 238000007670 refining Methods 0.000 claims description 17
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 14
- 238000003756 stirring Methods 0.000 claims description 11
- 238000010079 rubber tapping Methods 0.000 claims description 10
- 238000003723 Smelting Methods 0.000 claims description 9
- 238000010791 quenching Methods 0.000 claims description 8
- 230000000171 quenching effect Effects 0.000 claims description 8
- 229910052786 argon Inorganic materials 0.000 claims description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 6
- 238000007664 blowing Methods 0.000 claims description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 5
- 229910045601 alloy Inorganic materials 0.000 claims description 5
- 239000000956 alloy Substances 0.000 claims description 5
- 239000003795 chemical substances by application Substances 0.000 claims description 5
- 238000009987 spinning Methods 0.000 claims description 4
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 3
- 229910000592 Ferroniobium Inorganic materials 0.000 claims description 3
- 229910052791 calcium Inorganic materials 0.000 claims description 3
- 239000011575 calcium Substances 0.000 claims description 3
- 238000006477 desulfuration reaction Methods 0.000 claims description 3
- 230000023556 desulfurization Effects 0.000 claims description 3
- 239000002245 particle Substances 0.000 claims description 3
- 239000002893 slag Substances 0.000 claims description 3
- 239000012535 impurity Substances 0.000 claims description 2
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 229910052748 manganese Inorganic materials 0.000 abstract description 6
- 239000000203 mixture Substances 0.000 abstract description 3
- 230000000052 comparative effect Effects 0.000 description 11
- 238000009740 moulding (composite fabrication) Methods 0.000 description 6
- 239000002994 raw material Substances 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 238000009628 steelmaking Methods 0.000 description 5
- 238000004321 preservation Methods 0.000 description 4
- 238000001514 detection method Methods 0.000 description 3
- 229910052750 molybdenum Inorganic materials 0.000 description 3
- 229910000859 α-Fe Inorganic materials 0.000 description 3
- 229910000805 Pig iron Inorganic materials 0.000 description 2
- 238000000137 annealing Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 239000000498 cooling water Substances 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 229910001339 C alloy Inorganic materials 0.000 description 1
- 229910000885 Dual-phase steel Inorganic materials 0.000 description 1
- 229910000746 Structural steel Inorganic materials 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 229910001562 pearlite Inorganic materials 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/30—Regulating or controlling the blowing
- C21C5/34—Blowing through the bath
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0006—Adding metallic additives
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/06—Deoxidising, e.g. killing
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/064—Dephosphorising; Desulfurising
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/10—Handling in a vacuum
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D11/00—Process control or regulation for heat treatments
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/009—Pearlite
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
本发明属于冷镦钢技术领域,具体涉及一种低马氏体含量免调质冷镦钢盘条的制造方法及其应用。冷镦钢盘条的主要化学成分范围为C:0.18~0.23%,Si:≤0.20%,Mn:1.50~1.80%,Nb:0.010~0.015%,Al:0.020~0.060%,P、S≤0.025%,Cr、Ni、Cu≤0.20%。本发明通过优化C、Mn、Nb等元素成分设计,结合制造方法,使热轧盘条显微组织中存在5%~10%的马氏体组织,有效提高了钢的屈强比和冷拉拔强化指数,使钢经过较小的拉拔减面率即可获得高的机械性能,并保持了良好的冷镦成型性能,实现了免调质热处理生产8.8级各类螺栓,显著降低了下游行业的加工成本。
Description
技术领域
本发明属于冷镦钢技术领域,涉及一种低马氏体含量免调质冷镦钢盘条,还涉及一种低马氏体含量免调质冷镦钢盘条的制造方法及应用。
背景技术
冷镦钢行业通常将C含量<0.25%的冷镦钢成为低碳冷镦钢,将C含量0.25~0.48%的冷镦钢成为中碳冷镦钢。高强度冷镦钢通常是指用于生产8.8级以上的螺栓类产品或8级以上的螺母类产品,不同强度级别的紧固件需要选用不同的冷镦钢钢种,并采用不同的加工工艺。目前8.8级高强度紧固件用钢通常为中碳优质碳素结构钢或中碳合金钢,成品紧固件需进行淬火回火处理,特别是8.8级螺栓类产品,国内基本全部通过调质热处理来保证最终的机械性能。
而通常6.8级以下的紧固件多采用非热处理型中碳和低碳冷镦钢制造,成品紧固件无需淬火回火处理,但低碳冷镦钢由于强度偏低难以满足8.8级紧固件的要求;在现有技术中涉及一些低碳冷镦钢的研究,例如CN200710036254.9高强度紧固件用非调质双相冷镦钢及其制造方法,其虽然为低碳冷镦钢,但是其为双相钢,盘条金相组织由马氏体和铁素体组织组成,含有15~30%马氏体,较多实践中发现,当马氏体含量超过15%时,虽然有利于机械性能的保证,但是下游用户在螺栓装配后,螺栓在服役受力的过程中会出现脆性断裂的问题,这是由于马氏体比例太高导致的。CN202011100975.3一种高强度紧固件用非调质冷镦钢盘条及其制备方法冷镦钢盘条元素组成按重量百分数计为C:0.16~0.18%,Si:≤0.20%,Mn:1.40~1.50%,P:≤0.008%,S:≤0.008%,Ti:0.05~0.06%,V:0.10~0.13%,Al:≤0.01%,N:60~90ppm,其余为Fe和不可避免的杂质,虽然也是低碳冷镦钢,但其生产出的盘条热轧强度太高,且冷拉拔后强度上升的过快,由于螺栓连接设计要求螺栓强度级别和被连接处需要匹配,否则会造成被连接处螺牙变形,发生连接失效,因此该强度的冷镦钢盘条不适合生产8.8级螺栓,也不能代替8.8级使用。
在实际应用中,为保证连接可靠性,8.8级螺栓的屈服强度通常为640~720Mpa、抗拉强度通常为800~900Mpa,屈强比≥0.8,为达到其要求,下游用户需要采用调质热处理。一方面,由于螺栓的螺杆部分几乎没有冷镦变形所产生的加工强化效应,为保证螺栓杆部的性能,要求冷拉拔后的钢丝强度及屈强比均要符合8.8级螺栓的要求。另一方面,热轧态原料强度和屈强比相对较低,要达到8.8级螺栓的要求需要大减面率的拉拔加工,通过加工强化提升屈服强度、抗拉强度和屈强比,但拉拔减面率的增加会显著降低拉拔后钢丝的冷镦性能,导致冷镦成型过程出现开裂。因此下游用户基本选择对拉拔后的钢丝进行退火处理或选择较小的拉拔减面率,而通过调质热处理的方式使螺栓获得高的机械性能,满足8.8级螺栓的要求。
开发一种热轧态拥有合适机械性能和良好塑性的冷镦钢盘条,使其经过较小的拉拔减面率机械性能就能达到8.8级螺栓的要求,实现免球化退火生产8.8级螺栓,是目前急需解决的问题。
发明内容
为了解决上述问题,本发明通过优化C、Mn、Nb等元素成分设计,结合创意性控轧控冷方案,使热轧盘条显微组织中存在5%~10%的马氏体组织,有效的提高了钢的屈强比和冷拉拔强化指数,但使钢经过较小的拉拔减面率即可获得高的机械性能,并保持了良好的冷镦成型性能,实现了免调质热处理生产8.8级各类螺栓,显著降低了下游行业的加工成本。
一种低马氏体含量免调质冷镦钢盘条的制造方法,其特征在于化学成分设计、转炉冶炼工序、LF精炼工序、RH真空精炼工序、方坯连铸工序、盘条轧制工序。下面对本发明的盘条制造方法做详细叙述。
化学成分设计:
本发明所述盘条化学成分设计按重量百分数计为C:0.18~0.23%,Si:≤0.20%,Mn:1.50~1.80%,Nb:0.010~0.015%,Al:0.020~0.060%,P、S≤0.025%,Cr、Ni、Cu≤0.20%。
本发明盘条成分相对于含Cr-Mo冷镦钢和含Cr冷镦钢,取消了Cr和Mo两个合金元素的使用,由于Cr、Mo都是对钢的显微组织转变影响显著的元素,取消其添加有利于对盘条进行轧后控冷。本发明盘条成分相对于含B冷镦钢取消了B元素的使用,更有利于盘条轧制后的显微组织控制。
综合来看,本发明盘条取消了Cr、Mo、B等提高热处理性能的传统合金元素,为后续采用控轧控冷控制组织转变,使盘条获得了精准的马氏体组织比例,有效的提高钢的屈强比和冷拉拔强化指数,并进一步实现免调质热处理生产8.8级各类螺栓提供了基本条件。
转炉冶炼工序:
转炉冶炼工序全程底吹氩搅拌,出钢温度≥1550℃,出钢碳控制在0.05%~0.10%范围内,同时出钢P、S≤0.010%;出钢1/4开始依次加入脱氧剂、合金、增碳剂、渣料。
LF精炼工序:
LF精炼工序前期采用铝粒强化脱氧和脱硫,并使用铝线将Al含量一次调整到位;LF出站前10分钟加入铌铁至目标成分,LF精炼全程采用小搅拌操作,小搅拌是指搅拌气体流量为30~50L/min,搅拌气体为氩气。
RH真空精炼工序:
采用高真空度,并保证充足的处理时间,其中真高空度要求<60Pa,处理时间要求≥30min。RH破空后通过喂丝机喂入适量纯钙线,软吹时间≥10min。
方坯连铸工序:
方坯连铸工序中包使用覆盖剂覆盖,连铸中包采用整体式塞棒中包,中包使用时间不超过9小时,水口直径35mm,水口使用时间不超过7h,方坯连铸工序连铸过热度控制在20~35℃,执行拉速不高于1.50m/min慢节奏恒拉速控制;结晶器采用电磁搅拌,其中电流280±10A,频率3±0.2Hz;二冷采用弱冷配水模式,比水量0.50L/kg;连铸过程采用碱性覆盖剂,加强大包水口与长水口之间的氩气保护,保持0.6~0.9Pa的微正压。
盘条轧制工序:
盘条精轧机组采用760~800℃低温控轧,轧后780~800℃低温吐丝。轧后控制冷却分为两个阶段:第一阶段采用1.0~1.5℃/s的冷却速度冷却至280~300℃,随后开启风机,采用24.0~26.0℃/s的冷却速度将盘条冷却至常温。
盘条轧制工序的控轧控冷是获得稳定的过冷奥氏体组织比例,并最终获得常温下精准的马氏体比例的重要条件。热轧盘条显微组织中属于铁素体型钢,通过存在5%~10%的马氏体组织,有效的提高了钢的屈强比和冷拉拔强化指数,但使盘条经过较小的拉拔减面率即可获得高的机械性能,并保持了良好的冷镦成型性能。本发明将轧制后的冷镦钢热轧盘条经过冷拉拔、冷镦成型,无需调质热处理,生产得到的螺栓能达到8.8级的要求。
附图说明
图1为实施例1生产的低马氏体含量免调质冷镦钢盘条的显微组织图。
图2为实施例2生产的低马氏体含量免调质冷镦钢盘条的显微组织图。
图3为对比例6生产的低马氏体含量免调质冷镦钢盘条的显微组织图。
具体实施方式
本发明:低马氏体含量免调质冷镦钢盘条HS-8(Φ9.0mm)的具体成分如下:
Wt,%
C | Si | Mn | P | S | Nb | Cr、Ni、Cu | Al |
0.18-0.23 | ≤0.20 | 1.50-1.80 | ≤0.025 | ≤0.025 | 0.010~0.015 | ≤0.20 | 0.020~0.060 |
盘条制造流程:转炉冶炼工序—LF精炼工序—RH真空精炼工序—方坯连铸工序—盘条轧制。
实施例1
1、成分设计
化学成分设计按重量百分数计为C:0.19%,Si:0.08%,Mn:1.58%,Nb:0.012%,Al:0.029%,P:0.016%,S:0.014%,Cr:0.06%,Ni:0.03%,Cu:0.02%。
2、转炉冶炼
转炉加入炼钢原料(炼钢原料为铁水、生铁和废钢,其中生铁占炼钢原料总重的95%,废钢占炼钢原料总重的5%,炼钢原料的总装入量120t/炉),冶炼转炉冶炼全程底吹氩搅拌,出钢温度1568℃,出钢C控制在0.06~0.08%,出钢P、S≤0.008%;出钢1/4开始依次加入脱氧剂、合金、增碳剂、渣料。
3、LF精炼
LF精炼工序前期采用铝粒强化脱氧和脱硫,并使用铝线将Al含量一次调整到位;LF出站前10分钟加入铌铁至目标成分,LF精炼全程采用小搅拌操作。
4、RH真空精炼
采用高真空度,并保证充足的时间,其中高空度要求<60Pa,真空时间40min。RH破空后通过喂丝机喂入适量纯钙线,软吹时间15min。
5、方坯连铸
方坯连铸工序中包使用覆盖剂覆盖,连铸中包采用整体式塞棒中包,中包使用时间9小时,水口直径35mm,水口使用时间7h,连铸过热度控制在25~28℃。执行拉速1.50m/min恒拉速控制;结晶器采用电磁搅拌,其中电流280±10A,频率3±0.2Hz;二冷采用弱冷配水模式,比水量0.50L/kg;连铸过程采用碱性覆盖剂,加强大包水口与长水口之间的氩气保护,实际正压0.7~0.8Pa。
6、盘条轧制
盘条采用高速线材生产线轧制,轧后通过吐丝机吐丝成圈,进入斯太尔摩控冷线上控制冷却,其中盘条精轧机组实际低温控轧温度765~790℃,实际吐丝温度781~798℃。控制冷却方案分两个阶段进行:第一阶段控制冷却范围是前20个保温罩对应的控冷线区间,采用间隔开启保温罩的方案控制冷却,即1#、3#、5#...19#等奇数编号保温罩全部开启,而2#、4#、6#...20#等偶数编号保温罩全部关闭,第一阶段将盘条冷却至282~296℃,实际冷却速度1.2~1.35℃/s;第二阶段控制冷却范围是20#保温罩之后的斯太尔摩控冷线区域,这一阶段采用2台风机将盘条快速冷却至常温,风机风量分别为100%、95%,实际冷却速度25℃/s;其余轧制参数均采用常规工艺即可。
实施例2
将实施例1步骤1中化学成分替换为按重量百分数计为化学成分设计按重量百分数计为C:0.22%,Si:0.11%,Mn:1.75%,Nb:0.014%,Al:0.036%,P:0.011%,S:0.008%,Cr:0.09%,Ni:0.02%,Cu:0.05%,其他条件同实施例1。
对比例1
将实施例1步骤1中化学成分替换为按重量百分数计为C:0.16%,其他条件同实施例1。
对比例2
将实施例1步骤1中化学成分替换为按重量百分数计为C:0.25%,其他条件同实施例1。
对比例3
将实施例1步骤1中化学成分替换为按重量百分数计为Mn:1.30%,其他条件同实施例1。
对比例4
将实施例1步骤1中化学成分替换为按重量百分数计为Mn:1.90%,其他条件同实施例1。
对比例5
将实施例1步骤6中控制冷却方案替换为保温罩全部关闭,以1.2℃/s冷却速度冷却至常温,其他条件同实施例1。
对比例6
将实施例1步骤6中控制冷却方案替换为开启风机风冷,以25℃/s冷却速度冷却至常温,其他条件同实施例1。
本发明实施例与对比例盘条热轧态冷拉拔后(冷拉拔时,经过通过单道次拉拔,拉拔减面率控制为15%),机械性能及冷顶锻性能如下表1:
表1
备注:1.冷拉拔后1/3冷顶锻性能合格,可满足8.8级螺栓的冷镦成型加工要求。
2.8.8级螺栓机械性能要求抗拉强度≥800MPa,屈服强度≥640Mpa,且屈强比≥0.8。
本发明实施例1、实施例2盘条显微组织检测结果如图1~图2,对比例6盘条显微组织检测结果如图3,显微组织检测标准为GB/T 13299。实施例1、实施例2盘条显微组织中马氏体比例均在5%~10%之间,其余显微组织为铁素体和珠光体。其中对比例1、3、5均是马氏体比例低于5%的,会导致冷拉拔后强度不足,无法满足8.8级螺栓的要求;对比例2、4、6是马氏体比例高于10%的,会导致冷拉拔后1/3冷顶锻开裂,也无法保证螺栓的冷镦成型。
Claims (5)
1.一种低马氏体含量免调质冷镦钢盘条的制造方法,其特征在于:所述冷镦钢盘条化学成分为:按重量百分数计为C:0.18~0.23%,Si:≤0.20%,Mn:1.50~1.80%,Nb:0.010~0.015%,Al:0.020~0.060%,P≤0.025%,S≤0.025%,Cr、Ni、Cu≤0.20%,其余为铁和不可避免的杂质;
制造方法包括转炉冶炼工序、LF精炼工序、RH真空精炼工序、方坯连铸工序、盘条轧制工序;
其中盘条轧制工序为:盘条经精轧机组采用760~800℃低温控轧,轧后780~800℃低温吐丝,轧后控制冷却分为两个阶段:第一阶段采用1.0~1.5℃/s的冷却速度冷却至280~300℃,随后开启风机,采用24.0~26.0℃/s的冷却速度将盘条冷却至常温,制造得到的盘条显微组织中存在5%~10%的马氏体组织;低马氏体含量免调质冷镦钢盘条,无需调质热处理,经过冷拉拔、冷镦成型生产8.8级螺栓。
2.根据权利要求1所述的低马氏体含量免调质冷镦钢盘条的制造方法,其特征在于:转炉冶炼工序全程底吹氩搅拌,出钢温度≥1550℃,出钢碳控制在0.05%~0.10%范围内,同时出钢P≤0.010%、S≤0.010%;出钢1/4开始依次加入脱氧剂、合金、增碳剂、渣料。
3.根据权利要求1所述的低马氏体含量免调质冷镦钢盘条的制造方法,其特征在于:LF精炼工序前期采用铝粒强化脱氧和脱硫,并使用铝线将Al含量一次调整到位;LF出站前10分钟加入铌铁至目标成分,LF精炼全程采用小搅拌操作。
4.根据权利要求1所述的低马氏体含量免调质冷镦钢盘条的制造方法,其特征在于:RH真空精炼工序,采用高真空度,并保证充足的时间,其中高真空度要求<60Pa,处理时间要求≥30min;RH破空后通过喂丝机喂入适量纯钙线,软吹时间≥10min。
5.根据权利要求1所述的低马氏体含量免调质冷镦钢盘条的制造方法,其特征在于:方坯连铸工序连铸过热度控制在20~35℃,执行慢节奏恒拉速控制,二冷采用中等强度冷却;连铸过程采用碱性覆盖剂,加强大包水口与长水口之间的氩气保护,保持0.6~0.9Pa的微正压。
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN202110424196.7A CN113151743B (zh) | 2021-04-20 | 2021-04-20 | 一种低马氏体含量免调质冷镦钢盘条的制造方法及其应用 |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN202110424196.7A CN113151743B (zh) | 2021-04-20 | 2021-04-20 | 一种低马氏体含量免调质冷镦钢盘条的制造方法及其应用 |
Publications (2)
Publication Number | Publication Date |
---|---|
CN113151743A CN113151743A (zh) | 2021-07-23 |
CN113151743B true CN113151743B (zh) | 2022-07-29 |
Family
ID=76869345
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN202110424196.7A Active CN113151743B (zh) | 2021-04-20 | 2021-04-20 | 一种低马氏体含量免调质冷镦钢盘条的制造方法及其应用 |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN113151743B (zh) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN114855093B (zh) * | 2022-03-28 | 2023-10-03 | 本钢板材股份有限公司 | 一种高冷镦成型性低碳低硅含铝冷镦钢热轧盘条及其制备方法 |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101220439B (zh) * | 2007-01-08 | 2010-05-19 | 宝山钢铁股份有限公司 | 高强度紧固件用非调质双相冷镦钢及其制造方法 |
JP6673535B1 (ja) * | 2019-03-28 | 2020-03-25 | 日本製鉄株式会社 | 高周波焼入れが実施される鋼 |
CN111659731B (zh) * | 2020-05-25 | 2022-02-01 | 中天钢铁集团有限公司 | 一种基于高速线材生产线的珠光体球化方法 |
CN112359275B (zh) * | 2020-10-15 | 2021-11-23 | 中天钢铁集团有限公司 | 一种高强度紧固件用非调质冷镦钢盘条及其制备方法 |
-
2021
- 2021-04-20 CN CN202110424196.7A patent/CN113151743B/zh active Active
Also Published As
Publication number | Publication date |
---|---|
CN113151743A (zh) | 2021-07-23 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US11015232B2 (en) | Seamless steel tube with high strength and toughness and manufacturing method therefor | |
CN108642381B (zh) | 一种屈服强度460MPa级热轧高韧性耐低温H型钢及其制备方法 | |
CN113025917A (zh) | 一种具有低强度高塑性免退火冷镦钢用盘条及其制造方法 | |
CN108929986B (zh) | 一种高强度耐磨汽车制动用热轧钢板及其生产工艺 | |
CN101333624B (zh) | 一种抗硫化氢应力腐蚀耐高压锻件及其制造方法 | |
CN111826587A (zh) | 一种大规格风电螺栓用冷镦钢热轧盘条及其制备方法 | |
CN110453150B (zh) | 一种Cr-B系低碳高强度冷镦钢盘条及其制造方法 | |
CN105112782A (zh) | 一种热轧态船用低温铁素体lt-fh40钢板及其生产方法 | |
CN113073259A (zh) | 一种免退火10.9级紧固件用冷镦钢盘条及其制造方法 | |
CN112813346A (zh) | 适用于6.8和8.8级耐候紧固件的冷镦钢及生产方法 | |
CN111530942A (zh) | 一种优质碳素结构钢的热轧工艺 | |
CN103361552A (zh) | V-N微合金化460MPa级厚板及其制造方法 | |
CN114058974B (zh) | 一种15.9级耐腐蚀高强度螺栓用钢及其生产方法和热处理方法 | |
CN106480373A (zh) | 一种9.8级紧固件用非调质冷镦钢盘条及其生产方法 | |
CN113151743B (zh) | 一种低马氏体含量免调质冷镦钢盘条的制造方法及其应用 | |
CN112063918B (zh) | 一种低温高韧性x90钢级热煨弯管用管线钢板及其制造方法 | |
CN113737099A (zh) | 可适应大变形量冷加工成型用工具钢及其制备方法和套筒及其制备方法 | |
CN115572912B (zh) | 一种经济型460MPa级别工程结构用钢板冷却均匀性控制方法 | |
CN116083806A (zh) | 一种耐延迟断裂14.9级调质螺栓用冷镦钢热轧盘条及其制备方法 | |
CN111235479B (zh) | 一种经济型管线钢的制造方法 | |
CN110284077B (zh) | 一种薄规格高韧性管线钢的制造方法 | |
CN114231703A (zh) | 一种高强度简化退火冷镦钢生产方法 | |
CN107587048B (zh) | 一种含钒氮耐大气腐蚀型钢钢水和耐大气腐蚀型钢及其生产方法 | |
CN106676417B (zh) | 含钒氮耐大气腐蚀型钢钢水和耐大气腐蚀型钢及其生产方法 | |
CN106676398B (zh) | 含钒钛氮耐大气腐蚀型钢钢水和耐大气腐蚀型钢及其生产方法 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PB01 | Publication | ||
PB01 | Publication | ||
SE01 | Entry into force of request for substantive examination | ||
SE01 | Entry into force of request for substantive examination | ||
GR01 | Patent grant | ||
GR01 | Patent grant |