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CN-121992182-A - Technological method for reducing heat treatment deformation of slender shaft spring steel parts

CN121992182ACN 121992182 ACN121992182 ACN 121992182ACN-121992182-A

Abstract

The invention relates to a process method for reducing heat treatment deformation of slender shaft spring steel parts, which comprises the steps of carrying out at least one pre-straightening process after quenching and before main tempering for determining the final mechanical property of the parts, and carrying out main straightening and low-temperature tempering after the main tempering, wherein the pre-straightening process comprises the steps of pre-tempering the parts at a temperature lower than the main tempering temperature and then carrying out pre-straightening, wherein the target value of the pre-straightening straightness is larger than the target value of the main straightening straightness. The invention effectively reduces the deformation of slender shaft spring steel parts and meets the requirement of straightness.

Inventors

  • WANG YI
  • WANG YANFANG
  • YANG SHUAIQI

Assignees

  • 中船汉光科技股份有限公司

Dates

Publication Date
20260508
Application Date
20251231

Claims (9)

  1. 1. A process method for reducing heat treatment deformation of slender shaft spring steel parts is characterized in that after quenching and before main tempering for determining the final mechanical properties of the parts, at least one pre-straightening process is carried out, and main straightening and low-temperature tempering are carried out after the main tempering; The pre-straightening process comprises the steps of pre-tempering the part at a temperature lower than the main tempering temperature and then pre-straightening, wherein the target value of the pre-straightening straightness is larger than that of the main straightening straightness.
  2. 2. The process for reducing the heat treatment deformation of the slender shaft spring steel parts according to claim 1, wherein the quenching method is that the parts are heated to 900 ℃ plus or minus 10 ℃ and kept for 70min plus or minus 10min before oil cooling.
  3. 3. The process for reducing the heat treatment deformation of the slender shaft spring steel parts according to claim 2, wherein the pre-tempering method is that the parts are heated to 200 ℃ plus or minus 10 ℃ and kept warm for 70min plus or minus 10min and then cooled down in air, the main tempering method is that the parts are heated to 500 ℃ plus or minus 10 ℃ and kept warm for 90 plus or minus 10min and then cooled down in oil, and the low-temperature tempering method is that the parts are heated to 200 ℃ plus or minus 10 ℃ and kept warm for 70min plus or minus 10min and then discharged from a furnace after being cooled down in a furnace.
  4. 4. A process for reducing the heat treatment distortion of elongated shaft spring steel parts according to claim 3, wherein the parts δb is 1800±75MPa, and the straightness is <0.4mm; the target value of the pre-straightening straightness is less than or equal to 0.4mm; the target value of the main straightening straightness is less than or equal to 0.3mm.
  5. 5. The process for reducing distortion of elongated shaft spring steel parts by heat treatment of claim 1, wherein said pre-tempering and low temperature tempering are carried out in a well tempering furnace, the parts being clamped in a non-stationary vertical suspension.
  6. 6. The process for reducing distortion of elongated shaft spring steel parts by heat treatment of claim 1, wherein said quenching and primary tempering are carried out in a vacuum furnace, and the parts are clamped in a non-stationary vertical suspension manner.
  7. 7. The process for reducing heat treatment deformation of elongated shaft spring steel parts according to claim 5 or 6, wherein the non-fixed vertical suspension mode is realized by a suspension fixture, the suspension fixture comprises a suspension frame and more than one suspension beam arranged on the suspension frame, the suspension beam is provided with more than one clamping position, and the clamping position comprises a conical hole penetrating through the suspension beam and a clearance groove communicated with the conical hole; The clearance groove is used for penetrating the straight line part of the part into the conical hole, the large diameter end of the conical hole is arranged at the upper side, and the diameter of the large diameter end of the conical hole is larger than that of the straight line part of the part and smaller than that of the large diameter part of the part so as to hang the part on the suspension beam, wherein the large diameter part of the part is arranged at two ends of the straight line part of the part.
  8. 8. A process for reducing the deformation of elongated shaft spring steel parts by heat treatment according to any one of claims 1-4, characterized in that the quenching and main tempering are carried out in a vacuum furnace, the straight parts of the parts are supported by at least two support points, and the parts are bound to two of the support points.
  9. 9. The process for reducing heat treatment deformation of slender shaft spring steel parts according to claim 8, wherein the parts are horizontally arranged in a vacuum furnace through a supporting tool, the supporting tool comprises a supporting frame and more than two supporting beams arranged on the supporting frame, the supporting beams are used for supporting straight parts of the parts, and large-diameter parts positioned at two ends of the straight parts of the parts are suspended.

Description

Technological method for reducing heat treatment deformation of slender shaft spring steel parts Technical Field The invention relates to the technical field of mechanical manufacturing, in particular to a process method for reducing heat treatment deformation of slender shaft spring steel parts. Background The spring steel is special for manufacturing elastic elements, has high tensile strength, elastic limit and fatigue strength, simultaneously requires good hardenability, elastic reduction resistance and surface quality, and is widely applied to the fields of automobiles, railways, machinery, energy equipment and the like. When the slender shaft spring steel part is processed by using the heat treatment equipment with the existing specification according to the traditional heat treatment scheme, the deformation is reduced by knocking and straightening after quenching and tempering in a vacuum furnace, and then the knocking stress is eliminated by low-temperature tempering. Although the method can ensure the tensile strength of the product, the deformation of the part is still serious after low-temperature tempering, the straightness of the product is difficult to ensure, and the product requirement cannot be met. Disclosure of Invention In view of the above, the invention provides a process method for reducing the heat treatment deformation of slender shaft spring steel parts, which effectively reduces the deformation and meets the requirement of straightness. The invention is realized by the following technical scheme: A process for reducing the heat treatment deformation of slender shaft spring steel parts includes such steps as pre-straightening, pre-tempering at a temp lower than the temp of primary tempering, and pre-straightening, where the target value of pre-straightening straightness is greater than that of primary straightening straightness. Further, the quenching method is that the temperature of the part is raised to 900 ℃ plus or minus 10 ℃, and the part is kept for 70min plus or minus 10min and then is cooled by oil. Further, the pre-tempering method is to heat the part to 200 ℃ plus or minus 10 ℃ and keep the temperature for 70min plus or minus 10min and then cool the part in air, the main tempering method is to heat the part to 500 ℃ plus or minus 10 ℃ and keep the temperature for 90 plus or minus 10min and then cool the part in oil, and the low-temperature tempering method is to heat the part to 200 ℃ plus or minus 10 ℃ and keep the temperature for 70min plus or minus 10min and then discharge the part after furnace cooling. Further, the part delta b is 1800+/-75 MPa, the straightness is less than 0.4mm, the target value of the pre-straightening straightness is less than or equal to 0.4mm, and the target value of the main-straightening straightness is less than or equal to 0.3mm. Further, the pre-tempering and the low-temperature tempering are performed in a well tempering furnace, and the parts are clamped in a non-fixed vertical hanging mode. Further, the quenching and the main tempering are carried out in a vacuum furnace, and the parts are clamped in a non-fixed vertical hanging mode. The non-fixed vertical hanging mode is achieved through a hanging tool, the hanging tool comprises a hanging frame and more than one hanging beam arranged on the hanging frame, the hanging beam is provided with more than one clamping position, the clamping position comprises a conical hole penetrating through the hanging beam and a clearance groove communicated with the conical hole, the clearance groove is used for enabling a part straight line portion to penetrate into the conical hole, the large diameter end of the conical hole is arranged at the upper side, the diameter of the large diameter end of the conical hole is larger than the diameter of the part straight line portion and smaller than the diameter of the part large diameter portion, and therefore the part is hung on the hanging beam, and the part large diameter portion is arranged at two ends of the part straight line portion. Further, the quenching and the main tempering are performed in a vacuum furnace, the straight parts of the parts are supported by at least two supporting points, and the parts are bound on two of the supporting points. Further, the part is horizontally arranged in the vacuum furnace through a supporting tool, the supporting tool comprises a supporting frame and more than two supporting beams arranged on the supporting frame, the supporting beams are used for supporting straight parts of the part, and large-diameter parts positioned at two ends of the straight parts of the part are suspended. Compared with the prior art, the invention has the beneficial effects that: 1. The invention integrates deformation control into a heat treatment process by carrying out a pre-straightening process at least once after quenching and before main tempering for determining the final mechanical property of the part. The pre-tempering red