WO2021026716A1 - 一种椭圆形无缝钢管制造方法 - Google Patents

一种椭圆形无缝钢管制造方法 Download PDF

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WO2021026716A1
WO2021026716A1 PCT/CN2019/100169 CN2019100169W WO2021026716A1 WO 2021026716 A1 WO2021026716 A1 WO 2021026716A1 CN 2019100169 W CN2019100169 W CN 2019100169W WO 2021026716 A1 WO2021026716 A1 WO 2021026716A1
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cold
tube
elliptical
manufacturing
seamless steel
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PCT/CN2019/100169
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English (en)
French (fr)
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蔡志刚
苏诚
杨晨
王涛
吕越
罗霞
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浙江久立特材科技股份有限公司
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Priority to PCT/CN2019/100169 priority Critical patent/WO2021026716A1/zh
Publication of WO2021026716A1 publication Critical patent/WO2021026716A1/zh

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
    • B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes

Definitions

  • the invention relates to the technical field of metallurgy, in particular to a method for manufacturing an oval seamless steel pipe.
  • the normal waste heat exhaust heat exchanger (normal waste exhaust) of nuclear power is one of the key equipment of nuclear island waste heat exhaust system.
  • the waste heat removal system must be used to discharge the waste heat from the reactor, so that the reactor core can be fully cooled to ensure a safe shutdown.
  • the main reason for the Fukushima nuclear accident in 2011 was that under the accident conditions, the reactor waste heat could not be discharged in time, the reactor temperature continued to rise and the reactor core was melted, and the fuel cladding material reacted with water in the molten state to produce a large amount of hydrogen, causing an explosion.
  • the invention provides a method for manufacturing an elliptical seamless steel pipe, which has the advantages of short production cycle and high yield.
  • the structure size and surface quality of the elliptical pipe during the cold drawing forming process meet the technical requirements.
  • a method for manufacturing an oval seamless steel pipe which is characterized in that it includes intermediate product cold working, final cold drawing, finished product heat treatment and straightening treatment steps, wherein:
  • the waste tube is cold-rolled, and the ratio of the final diameter D0 of the cold-rolled tube to the diameter D1 in the long axis direction of the elliptical tube is controlled at 1.10-1.50;
  • the middle round tube is cold drawn into an oval tube by air drawing or cold drawing with core diameter, and the cold drawing speed is 1.0 ⁇ 10.0m/min;
  • Black annealing or bright annealing is used for heat treatment of finished products, the annealing temperature is 1050-1100°C, the holding time is determined according to the wall thickness of the oval tube WT1, and the holding time is (1.0-3.0)*WT1min/mm.
  • thermal perforation is used to provide the waste pipe, and the waste pipe is subjected to straightening, pickling, surface inspection and grinding treatment.
  • the maximum outer diameter of the head after the heading does not exceed the diameter of the elliptical pipe in the minor axis direction.
  • At least two passes of cold rolling are carried out in the cold working of the intermediate product, and the cold-rolled round pipes of each pass are subjected to black annealing or bright annealing heat treatment.
  • the surface roughness Ra of the working area of the cold drawing die is not more than 0.2um
  • the cone angle of the deformation section of the cold drawing die is not less than 8°
  • the length of the sizing section of the cold drawing die is not less than 1.0mm.
  • a protective atmosphere bright annealing furnace is used for solution treatment, the protective atmosphere is hydrogen, the purity is greater than 99.95%, the dew point of the gas source is ⁇ -50°C, and the grain size is controlled at 5.0-7.0 during the heat treatment of the finished product. level.
  • a flat roll pressure straightening method is used for plane straightening.
  • the oval tube stainless steel is TP304L austenitic stainless steel.
  • the elliptical seamless steel pipe has high dimensional accuracy, small flatness, controlled grain size at 5.0-7.0, excellent mechanical properties, and good surface quality; cold rolling and cold drawing of elliptical pipes are used for waste pipes
  • the process by controlling the diameter and wall thickness of the cold-rolled round tube, realizes the dimensional accuracy and surface quality requirements of the cold-drawn formed elliptical tube.
  • the invention provides a method for manufacturing an elliptical seamless steel pipe.
  • the standard dimensions of the elliptical steel pipe are: major axis diameter 18.67 ⁇ 0.1mm, major axis diameter 24.05 ⁇ 0.25mm, parallel section wall thickness 3 ⁇ 0.3mm, arc section wall thickness 3 ⁇ 0.3 mm. It uses TP304L austenitic stainless steel, and the chemical composition of the TP304L stainless steel tube blank should comply with the corresponding regulations in ASTM A213 or GB 13296-2013.
  • the method includes the following steps:
  • TP304L waste pipe is made by thermal perforation method. After the waste pipe is straightened and pickled, the surface inspection and grinding treatment are carried out to ensure that there are no defects on the surface that affect the subsequent cold processing.
  • the final cold-rolled finished pipe has an outer diameter and tolerance of 27 ⁇ 0.10mm, and a wall thickness and tolerance of 3.0 ⁇ 0.15mm.
  • the outer diameter of the final cold-rolled tube is larger than the diameter of the long axis of the elliptical tube to ensure that the long axis can be filled and avoid surface strain.
  • the final cold-rolled round tube wall thickness is basically equivalent to that of the oval tube.
  • the annealing of the intermediate tube is black annealing, the annealing temperature is 1080 °C, and the holding time is 15 min and 9 min, respectively.
  • Annealing should be solid solution enough to ensure that the intermediate tube has relatively low strength and good elongation, so that the final cold drawing can be carried out smoothly, and no surface strain will occur due to excessive strength.
  • the middle tube is cold drawn to a 24*18mm elliptical tube, and the relative deformation is about 15%.
  • the special cold drawn lubricant is used for continuous lubrication during the cold drawing process, and the cold drawing speed is 6m/min. Avoid surface strain and bouncing phenomenon, so as not to affect the surface quality of the final product, while taking into account the production efficiency.
  • the dimensions of the oval tube after cold drawing are shown in Table 2.
  • the elliptical tube is finally cold-drawn into shape for air-drawn or cold-drawn with core diameter.
  • the cold drawing mold adopts tungsten steel mold, the cone angle of the deformation section of the cold drawing mold is not less than 12°, the surface roughness Ra of the working area of the cold drawing mold is not more than 0.2um, and the length of the sizing section of the cold drawing outer mold is not less than 2mm.
  • a certain amount of springback needs to be considered, usually based on 0.05% to 0.5% of the finished product size.
  • the heat treatment of the finished product adopts a protective atmosphere bright annealing furnace for solution treatment, the set temperature is 1080 °C, the holding time is 6 min, the protective atmosphere is hydrogen, the purity is greater than 99.95%, and the dew point of the gas source is ⁇ -50°C.
  • the solid solution is sufficient, the structure is uniform, and the grain size is controlled at 5.0-7.0.
  • the pipe After the heat treatment, the pipe is mainly bent along the short axis, and the flat roller pressure straightening technology is used for plane straightening. During the straightening process, excessive straightening, pitting, bruising, etc. are not allowed, and the surface defects must be ground.
  • the finished tube is sampled for organization and mechanical performance testing.
  • the finished tube has a grain size of 7.0, which meets the requirement of a grain size greater than 4.0 in the technical specifications.
  • the room temperature mechanical properties are shown in Table 3, which meets the technical requirements.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Heat Treatment Of Steel (AREA)
  • Heat Treatment Of Articles (AREA)
  • Metal Extraction Processes (AREA)

Abstract

一种椭圆形无缝钢管制造方法，包括中间品冷加工、最终冷拔、成品热处理以及矫直处理工序；中间品冷加工工序对圆管荒管进行冷轧加工，最终冷轧圆管外径D0与椭圆管长轴方向的直径D1的比例控制在1.10-1.50；最终冷拔工序采用空拔或带芯径冷拔将中间圆管冷拔成椭圆管，冷拔速度为1.0-10.0m/min；采用黑退火或光亮退火进行成品热处理，退火温度1050-1100℃，保温时间根据椭圆管壁厚WT1确定，保温时间为（1.0-3.0）×WT1 min/mm。

Description

一种椭圆形无缝钢管制造方法 技术领域
本发明涉及冶金技术领域，尤其涉及一种椭圆形无缝钢管制造方法。
背景技术
核电正常余热排出热交换器(正常余排)是核岛余热排出系统关键设备之一。核电站在正常停堆检修或事故工况下紧急停堆时，必须利用余热排出系统将反应堆中的余热排出，使得反应堆堆芯充分冷却，确保安全停堆。2011年福岛核事故主要原因就是由于事故工况下，反应堆余热未能及时排出，反应堆温度不断升高导致堆芯熔融，燃料包壳材料在熔融状态下与水反应产生大量氢气造成爆炸。
每台正常余排中有近一千多支壁厚仅1.24mm左右的不锈钢换热管分层布置，在工况条件下，换热管承受高温高压水流冲击，如果不对换热管进行约束，则在高温高压水流冲击下大量的换热管之间会发生振动，造成相互碰撞、磨损以及与支撑板之间的磨损，容易导致换热管破裂失效，从而造成余热排出系统失效，导致核事故发生。椭圆管抗震条的主要作用就是防止换热管在工况下发生振动、碰撞和磨损，确保正常余排安全有效工作，因此椭圆管也是核电站重要的核安全部件之一，对不锈钢椭圆管的力学性能以及尺寸精度要求较高。
发明概述
技术问题
问题的解决方案
技术解决方案
本发明提供了一种椭圆形无缝钢管制造方法，具有生产周期短、良品率高的优点，椭圆管冷拔成型过程中结构尺寸与表面质量符合技术要求。
为了达到所述目的，本发明采用如下技术方案：
一种椭圆形无缝钢管制造方法，其特征在于，包括中间品冷加工、最终冷拔、成品热处理以及矫直处理工序，其中：
中间品冷加工中对圆管荒管进行冷轧加工，最终冷轧圆管外径D0与椭圆管长轴方向的直径D1的比例控制在1.10-1.50；
最终冷拔工序中，采用空拔或带芯径冷拔将中间圆管冷拔成椭圆管，冷拔速度为1.0～10.0m/min；
采用黑退火或光亮退火进行成品热处理，退火温度1050-1100℃，保温时间根据椭圆管壁厚WT1确定，保温时间为(1.0-3.0)*WT1min/mm。
作为一种优选，采用热穿孔提供所述荒管，对所述荒管进行矫直、酸洗、表面检查和修磨处理。
作为一种优选，所述荒管矫直后进行打头处理，打头后头部的最大外径不超过椭圆管短轴方向的直径。
作为一种优选，中间品冷加工中至少进行两道次的冷轧处理，对各道次冷轧处理圆管进行黑退火或光亮退火热处理。
作为一种优选，最终冷拔工序中，冷拔模工作区表面粗糙度Ra不超过0.2um，冷拔模具变形段锥角不小于8°，冷拔外模具定径段长度不小于1.0mm。
作为一种优选，成品热处理工序中采用保护气氛光亮退火炉进行固溶处理，保护气氛为氢气，纯度大于99.95％，气源露点≤-50℃，成品热处理过程中晶粒度控制在5.0-7.0级。
作为一种优选，矫直处理工序中，采用平辊压力矫直方法进行平面矫直。
作为一种优选，椭圆管不锈钢为TP304L奥氏体不锈钢。
发明的有益效果
有益效果
本发明的优点在于：该椭圆形无缝钢管尺寸精度高、平面度小，晶粒度控制在5.0-7.0级，力学性能优异，表面质量好；对荒管采用冷轧加椭圆管冷拔加工工艺，通过对冷轧圆管直径和壁厚控制，实现冷拔成型椭圆管的尺寸精度与表面质量要求。
发明实施例
本发明的实施方式
下面结合具体实施例对本发明作进一步说明。
本发明提供的一种椭圆形无缝钢管制造方法，椭圆形钢管标准尺寸为：长轴直径18.67±0.1mm，长轴直径24.05±0.25mm，平行段壁厚3±0.3mm，圆弧段壁厚3±0.3mm。其采用TP304L奥氏体不锈钢，TP304L不锈钢管坯的化学成分应符合ASTM A213或GB 13296-2013标准中相应规定。所述方法包括以下步骤：
1)热加工
采用热穿孔方法制成TP304L荒管，荒管规格为
Figure PCTCN2019100169-appb-000001
荒管矫直、酸洗后进行表面检查和修磨处理，确保表面不存在影响后续冷加工的缺陷存在。
2)中间管冷加工及热处理
采用大变形冷轧工艺，中间管冷加工变形道次如表1所示。
表1冷加工变形道次
道次 D0(mm) S0(mm) D1(mm) S1(mm) ζ λ 备注
1 78 8.0 45 5.0 2.80 0.64 冷轧
2 45 5.0 27 3.0 2.78 0.64 冷轧
轧制过程中内外表面须充分润滑，轧制过程中逐支进行外表面质量检查，内外表面不得有裂纹、折叠、轧伤、压坑等轧制缺陷。最终冷轧成品管外径及公差27±0.10mm，壁厚及公差3.0±0.15mm。最终冷轧成品管外径大于椭圆管长轴方向直径，以保证长轴方面能够被填充满，同时避免表面拉伤。最终冷轧圆管壁厚与椭圆管壁厚基本相当。
Figure PCTCN2019100169-appb-000002
和
Figure PCTCN2019100169-appb-000003
中间管退火均采用黑退火，退火温度1080℃，保温时间分别为15min和9min。退火应固溶充分，确保中间管具有相对较低的强度和较好的延伸率，使得最终冷拔能顺利进行，不至于因强度过高出现表面拉伤现象。
退火后矫直、酸洗，确保表面无氧化皮、残酸、过酸等现象存在。圆管坯料经矫直后对表面进行检查，不得有裂纹、折叠、压坑、碰伤等影响后续产品质量的严重缺陷存在。矫直后打头处理，打头后头部的最大外径不超过椭圆管短轴方向的直径，以确保打头部位能顺利穿过冷拔模具。
3)成品冷拔
Figure PCTCN2019100169-appb-000004
中间管冷拔至24*18mm椭圆管，相对变形量15％左右，冷拔过程中采用专用冷拔润滑油连续润滑，冷拔速度6m/min。避免产生表面拉伤和弹跳现象 ，以免影响最终成品的表面质量，同时兼顾生产效率。冷拔后椭圆管尺寸如表2所示。
椭圆管最终冷拔成形进行空拔或带芯径冷拔。冷拔模具采用钨钢模具，冷拔模具变形段锥角不小于12°，冷拔模工作区表面粗糙度Ra不超过0.2um，冷拔外模具定径段长度不小于2mm。需考虑一定的回弹量，通常按成品尺寸的0.05％～0.5％考虑。
表2椭圆管尺寸(mm)
Figure PCTCN2019100169-appb-000005
4)成品热处理与矫直
成品热处理采用保护气氛光亮退火炉进行固溶处理，设定温度1080℃，保温时间6min，保护气氛为氢气，纯度大于99.95％，气源露点≤-50℃。热处理过程中固溶充分，组织均匀，晶粒度控制在5.0-7.0级。确保成品管材具有较高的力学性能，且管材内外表面不发生氧化变色现象，保证管材具有较好的表面质量。
热处理后管材主要是沿短轴方面弯曲，采用平辊压力矫直技术进行平面矫直。矫直过程中不允许存在过度矫直、压坑、碰伤等现象，需对表面缺陷部位进行修磨处理。
成品管取样进行组织和力学性能检测。成品管晶粒度为7.0级，符合技术条件规定的晶粒度大于4.0级的要求。室温力学性能如表3所示，符合技术条件要求。
表3椭圆管成品室温力学性能
项目 R m(MPa) R p0.2(MPa) A(％)(L 0＝50mm)
标准值 ≥515 ≥205 ≥30
检测结果 600 280 46
以上说明仅仅是对本发明的解释，使得本领域普通技术人员能完整的实施本方案，但并不是对本发明的限制，本领域技术人员在阅读完本说明书后可以根据需要对本实施例做出没有创造性贡献的修改，这些都是不具有创造性的修改，但只要在本发明的权利要求范围内都受到专利法的保护。

Claims (8)

  1. 一种椭圆形无缝钢管制造方法，其特征在于，包括中间品冷加工、最终冷拔、成品热处理以及矫直处理工序，其中：
    中间品冷加工中对圆管荒管进行冷轧加工，最终冷轧圆管外径D0与椭圆管长轴方向的直径D1的比例控制在1.10-1.50；
    最终冷拔工序中，采用空拔或带芯径冷拔将中间圆管冷拔成椭圆管，冷拔速度为1.0～10.0m/min；
    采用黑退火或光亮退火进行成品热处理，退火温度1050-1100℃，保温时间根据椭圆管壁厚WT1确定，保温时间为WT1*(1.0～3.0)min/mm。
  2. 根据权利要求1所述的一种椭圆形无缝钢管制造方法，其特征在于：采用热穿孔提供所述荒管，对所述荒管进行矫直、酸洗、表面检查和修磨处理。
  3. 根据权利要求2所述的一种椭圆形无缝钢管制造方法，其特征在于：所述荒管矫直后进行打头处理，打头后头部的最大外径不超过椭圆管短轴方向的直径。
  4. 根据权利要求1所述的一种椭圆形无缝钢管制造方法，其特征在于：中间品冷加工中至少进行两道次的冷轧处理，对各道次冷轧处理圆管进行黑退火或光亮退火热处理。
  5. 根据权利要求1所述的一种椭圆形无缝钢管制造方法，其特征在于：最终冷拔工序中，冷拔模工作区表面粗糙度Ra不超过0.40um，冷拔模具变形段锥角不小于8°，冷拔外模具定径段长度不小于1.0mm。
  6. 根据权利要求1所述的一种椭圆形无缝钢管制造方法，其特征在于：成品热处理工序中采用保护气氛光亮退火炉进行固溶处理，保护气氛为氢气，纯度大于99.95％，气源露点≤-50℃，成品热处理过程中晶粒度控制在5.0-8.0级。
  7. 根据权利要求1所述的一种椭圆形无缝钢管制造方法，其特征在于 ：矫直处理工序中，采用平辊压力矫直方法进行平面矫直，如果发生扭曲，可采用拉力矫直进行拉矫。
  8. 根据权利要求1所述的一种椭圆形无缝钢管制造方法，其特征在于：椭圆管不锈钢为奥氏体不锈钢，同样适用于铁素体不锈钢以及奥氏体组织的耐蚀合金和高温合金。
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