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CN-122013033-A - High-performance spheroidal graphite cast iron for reciprocating piston compressor unit and smelting process thereof

CN122013033ACN 122013033 ACN122013033 ACN 122013033ACN-122013033-A

Abstract

The invention relates to the technical field of compressors, in particular to high-performance spheroidal graphite cast iron for a reciprocating piston compressor unit and a smelting process thereof. The high-performance spheroidal graphite cast iron for the reciprocating piston compressor unit comprises the following chemical elements of, by weight, 3.2-3.6% of C, 2.4-2.9% of Si, 0.3-0.4% of Mn, less than or equal to 0.05% of P, less than or equal to 0.03% of S, 0.03-0.06% of Mg, 0.01-0.05% of rare earth metal, less than or equal to 0.04% of Ti, less than or equal to 0.03% of Sb, 0.3-0.6% of Cu+Ni, and the balance of iron and unavoidable impurities. According to the invention, based on the traditional QT450-10 spheroidal graphite cast iron, nickel and copper elements are introduced, so that the mechanical property of the spheroidal graphite cast iron is improved, and the manufactured compression cylinder product meets the requirement of a use scene with higher requirements on the compression cylinder.

Inventors

  • ZHOU HUI
  • DENG JING
  • WANG HAOYU
  • Deng Ganyin
  • ZHOU YOU
  • WANG YIGEN
  • XIANG JIN
  • YAN YONG
  • QIN MING
  • LIAO YULONG
  • YANG RUIXIN
  • CHEN YONG
  • WU GUANGLEI
  • LI YAO
  • TAN XUEMU
  • YANG JIE
  • HUANG HAO
  • YANG PENG
  • ZENG ZEPING
  • HUANG MIN
  • GAO YANG
  • CHEN YU
  • YAN YONGCHENG
  • LI JIAN
  • LI SHENG
  • JIANG YONG
  • DUAN YUEHONG
  • ZOU QING
  • HUA XUN
  • LONG YUN
  • LONG JIE
  • LIU XIAOLIN
  • MENG RENJIE
  • Xiao Yaxi
  • WU SIJUN
  • LI SHANGCHUN
  • WANG TIGANG
  • LIU XIN
  • HUANG JIAWEI

Assignees

  • 中国石油天然气集团有限公司
  • 中国石油集团济柴动力有限公司

Dates

Publication Date
20260512
Application Date
20241111

Claims (10)

  1. 1. The high-performance spheroidal graphite cast iron for the reciprocating piston compressor unit is characterized by comprising the following chemical elements in percentage by weight: 3.2-3.6wt% of C, 2.4-2.9wt% of Si, 0.3-0.4wt% of Mn, less than or equal to 0.05wt% of P, less than or equal to 0.03wt% of S, 0.03-0.06 wt% of Mg, 0.01-0.05wt% of rare earth metal, less than or equal to 0.04wt% of Ti, less than or equal to 0.03wt% of Sb, 0.3-0.6wt% of Cu+Ni, and the balance of iron and unavoidable impurities.
  2. 2. The process for smelting high-performance spheroidal graphite cast iron for a reciprocating piston compressor unit according to claim 1, comprising the steps of: 1) Preparing pig iron, carburant, scrap steel, return furnace material and alloy material; 2) Smelting, namely based on high-current rapid smelting, smelting pig iron in a furnace, sequentially adding carburant, scrap steel, furnace return materials and alloy materials, and heating to obtain cast iron liquid; 3) And casting, namely discharging the cast iron liquid out of the furnace, spheroidizing, and casting to obtain the high-performance spheroidal graphite cast iron for the reciprocating piston compressor unit.
  3. 3. The smelting process according to claim 2, wherein the temperature of the pig iron in the furnace is 1220-1350 ℃.
  4. 4. The smelting process according to claim 2, wherein the smelting is performed in step 2), the temperature is raised to 1480-1530 ℃ and maintained for 3-10 min.
  5. 5. The smelting process according to claim 2, wherein the step 2) is performed by sampling analysis during the heating smelting process and detecting the chemical component content of the molten steel, and if the chemical component content of the molten steel is not acceptable, adding a carburant, scrap steel, a furnace return material or an alloy material into the molten steel, and adjusting the chemical component content of the molten steel until the sampling analysis is acceptable.
  6. 6. The smelting process according to claim 5, wherein the sampling analysis includes sampling to detect C, si content in molten steel at a molten steel temperature of 1400-1430 ℃.
  7. 7. The smelting process according to claim 6, wherein the sampling analysis further comprises sampling stokehole spectroscopic analysis at a molten steel temperature of 1420-1450 ℃.
  8. 8. The smelting process according to claim 2, wherein the tapping temperature of the cast iron liquid is 1440-1480 ℃ in step 3).
  9. 9. The smelting process according to claim 2, wherein the casting is performed in step 3) and the spheroidization is performed at 1400 ℃.
  10. 10. The smelting process according to claim 2, wherein the casting is performed in step 3) by scraping dross from the surface of the molten iron prior to casting.

Description

High-performance spheroidal graphite cast iron for reciprocating piston compressor unit and smelting process thereof Technical Field The invention relates to the technical field of compressors, in particular to high-performance spheroidal graphite cast iron for a reciprocating piston compressor unit and a smelting process thereof. Background Since the invention of the 20 th century 40, the ball-and-ink casting has been widely used in various fields because of its high strength, corrosion resistance, oxidation resistance, excellent mechanical properties such as shock absorbing ability, and low production cost. The reciprocating piston type natural gas compressor plays an important role in peak regulation and supply protection of oil and gas resources, and the spheroidal graphite cast iron compression cylinder is used as one of core parts of the reciprocating piston type natural gas compressor, and has more strict requirements on mechanical properties of castings due to various characteristics of severe use environment, complex stress, long service period and the like. At present, the manufacturing of the compression cylinder mainly adopts ductile cast iron with the brand of QT450-10, the requirement value of the ductile cast iron on tensile strength is 450MPa, the requirement value of elongation is 10%, the main matrix structure is ferrite, the chemical composition is C3.4-3.8 wt%, si 2.1-2.7 wt%, mn 0.30-0.40 wt%, P less than or equal to 0.05wt%, mg 0.04-0.65 wt%, rare earth metal 0.01-0.05 wt%, and the balance is iron and unavoidable impurities. However, as the application of reciprocating piston type natural gas compressors is wider and wider, the requirements on power and pressure are higher and higher, and the performance of spheroidal graphite cast iron with the mark QT450-10 needs to be improved so as to improve the mechanical performance of the spheroidal graphite cast iron. In the prior art, CN104264033a discloses a high-strength high-rigidity spheroidal graphite cast iron material for compressors. The nodular cast iron material is applied to manufacturing upper and lower bearings of a compressor, and can obviously improve the strength and rigidity of the upper and lower bearings. However, it has poor toughness and is difficult to use as a compression cylinder. CN106048400a discloses a spheroidal graphite cast iron for compressor cylinder and its preparation method, the spheroidal graphite cast iron includes several non-metal, metal and transition metal elements, these elements are added and mutually matched, so that the oxidation resistance, corrosion resistance, abrasion resistance and compression resistance and shock resistance of air conditioner compressor cylinder can be raised, and the service life of air conditioner compressor cylinder under the condition of severe working condition can be prolonged. However, the tensile strength of the ductile cast iron reaches 650MPa or more, but the elongation is 12.0% at most, the elongation requirement value is not greatly improved relative to QT450-10, and the main matrix structure of the ductile cast iron is pearlite. Therefore, developing spheroidal graphite cast iron with excellent comprehensive mechanical properties to meet the use of compression cylinders with strict requirements remains challenging. Disclosure of Invention The invention provides a high-performance spheroidal graphite cast iron for a compound piston compressor unit and a smelting process thereof, wherein the use proportion of carbon (C), silicon (Si), manganese (Mn) and sulfur (S) elements in the conventional spheroidal graphite cast iron is changed, the residual quantity of magnesium (Mg) is controlled, nickel (Ni) and copper (Cu) elements are introduced, the sum of the introduced contents of nickel and copper is clarified, and the mechanical property of the spheroidal graphite cast iron is improved. The high-performance spheroidal graphite cast iron for the reciprocating piston compressor unit comprises the following chemical elements in percentage by weight: 3.2-3.6wt% of C, 2.4-2.9wt% of Si, 0.3-0.4wt% of Mn, less than or equal to 0.05wt% of P, less than or equal to 0.03wt% of S, 0.03-0.06 wt% of Mg, 0.01-0.05wt% of rare earth metal, less than or equal to 0.04wt% of Ti, less than or equal to 0.03wt% of Sb, 0.3-0.6wt% of Cu+Ni, and the balance of iron and unavoidable impurities. In the chemical composition of the high-performance spheroidal graphite cast iron for the reciprocating piston compressor unit, both carbon (C) and silicon (Si) elements promote the spheroidization of the spheroidal graphite cast iron, improve the mechanical strength of a spheroidal graphite cast iron matrix structure, but the excessive silicon content can directly influence the low-temperature impact property of a spheroidal graphite cast iron product, and when the silicon content exceeds 3.0wt% on the premise of unchanged content of other elements, the low-temperature impact property is reduced to be l