An iron-based alloy and a method for producing a rod thereof

Abstract

The present application relates to the technical field of high-temperature alloy, and provides an iron-based alloy and a preparation method of a rod thereof.The iron-based alloy comprises Co 19.5% to 20.5%, Cr 5.8% to 6.2%, Mo 9.5% to 10.5%, C > 0.01% and ≤ 0.05%, and the balance is Fe and inevitable impurities.The preparation method of the rod comprises the following steps: vacuum induction smelting electrolytic cobalt sheets, metal chromium blocks, metal molybdenum strips, pure iron rods and carbon powder according to the proportions to obtain alloy steel liquid; high-temperature refining the alloy steel liquid to obtain pure alloy steel liquid; pouring the pure alloy steel liquid into an alloy rod mold through a sprue to obtain alloy cast rod through steel pouring refining; and cutting and grinding the alloy cast rod to obtain the iron-based alloy rod.The present application can significantly improve the wear resistance and processing performance of the iron-based alloy, and can also enable the iron-based alloy to maintain excellent impact toughness and strength in a wide temperature range of-100 DEG C to 800 DEG C.

Description

Technical Field

[0001] This invention relates to the field of high-temperature alloy technology, and in particular to an iron-based alloy and a method for preparing its rods. Background Technology

[0002] Mechanical moving parts in transportation, petroleum, chemical, and shipbuilding industries and machinery are subjected to intense friction, wear, and impact at high temperatures. These parts require materials that meet impact toughness and strength requirements at high temperatures, while also possessing superior wear resistance. Existing iron-based alloy materials generally meet the requirements for impact toughness and strength, but their wear resistance is still not ideal. Therefore, it is necessary to conduct further in-depth research on the wear resistance of iron-based alloy materials to meet the higher demands of industrial equipment. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides an iron-based alloy and a method for preparing its bars, which can significantly improve the wear resistance and processing performance of the iron-based alloy. At the same time, it can also enable the iron-based alloy to maintain excellent impact toughness and strength in a wide temperature range of -100℃ to 800℃, and can be widely used in mechanical moving parts of industrial and mechanical equipment in transportation, petroleum, chemical and shipbuilding industries.

[0004] The technical solution of this invention is as follows: An iron-based alloy, comprising the following components by mass percentage: Co: 19.5%~20.5%, Cr: 5.8%~6.2%, Mo: 9.5%–10.5%, C: >0.01% and ≤0.05%, The balance is Fe and unavoidable impurities.

[0005] Furthermore, by mass percentage, it includes the following components: Co: 20.0%, Cr: 6.1% Mo: 10.0%, C: 0.04%, The balance is Fe and unavoidable impurities.

[0006] Furthermore, by mass percentage, it includes the following components: Co: 20.0%, Cr: 5.9% Mo: 10.0%, C: 0.02%, The balance is Fe and unavoidable impurities.

[0007] A method for preparing bars of the iron-based alloy includes the following steps: Step 1: According to the mass percentages of Co, Cr, Mo, Fe, and C in the iron-based alloy, place electrolytic cobalt sheets, metallic chromium blocks, metallic molybdenum bars, pure iron rods, and carbon powder into the crucible of a vacuum induction melting furnace for vacuum induction melting to obtain alloy steel liquid. Step 2: The alloy steel liquid is refined at high temperature to obtain pure alloy steel liquid; Step 3: Pour the pure alloy steel liquid into the alloy rod mold through the gating system to obtain the alloy casting rod; Step 4: Cut and grind the alloy casting rod to obtain the iron-based alloy rod.

[0008] Furthermore, in step 1, the electrolytic cobalt sheet and the metallic chromium block have an external diameter of no more than 50 mm, the metallic molybdenum strip and the pure iron rod have a diameter of no more than 30 mm and a length of no more than 400 mm, and the carbon powder has a particle size of no more than 60 mesh and a purity of no less than 99.5%.

[0009] Furthermore, in step 1, the clearing time of the vacuum induction melting is controlled at 3.0-4.0 hours, and the vacuum degree is controlled at below 5 Pa.

[0010] Furthermore, in step 2, the temperature of the high-temperature refining is controlled at 1500-1600℃, the vacuum degree is controlled below 0.1Pa, and the time is controlled at 20-40min.

[0011] Furthermore, in step 3, the temperature of the steel casting is controlled at 1450-1500℃, the vacuum degree is controlled below 5Pa, the steel casting time is controlled within 2 minutes, the diameter of the alloy casting rod is controlled at 50-150mm, and it is taken out of the furnace after cooling for 3-5 minutes.

[0012] Furthermore, in step 4, the cutting includes cutting the rod head and the rod tail, with each head having a cut length of not less than 10mm, and the grinding includes grinding the rod head, the rod tail, and the rod body.

[0013] The beneficial effects of this invention are as follows: (1) By adding Co, Cr and Mo elements to the iron alloy matrix, the present invention can form stable compounds within the designed mass percentage range. These compounds have high purity and low oxygen content, which significantly improves the wear resistance and processing performance of the iron-based alloy. At the same time, the iron-based alloy can maintain excellent impact toughness and strength in a wide temperature range of -100℃ to 800℃, with a hardness of 45-65HRC and an impact toughness (U-notch) of 3.3 to 4.0J / cm².

[0014] (2) This invention obtains iron-based alloy rods by sequentially vacuum induction melting, high-temperature refining, gating casting, cutting, and grinding electrolytic cobalt sheets, metallic chromium blocks, metallic molybdenum bars, pure iron rods, and carbon powder according to the proportions of each element in the iron-based alloy. Furthermore, the dimensions of each raw material and the time, temperature, vacuum degree, and other parameters of each step are designed. The vacuum induction melting process can effectively remove oxygen, nitrogen, hydrogen gas impurities, as well as low-melting-point and volatile elements from the raw materials, while completing alloying and promoting the homogenization of the alloy. It effectively avoids the large-scale burning loss of Cr and C elements and minimizes the introduction of impurity elements, effectively ensuring the composition content of Co, Cr, Mo, Fe, and C in the iron-based alloy. The resulting iron-based alloy has high impact toughness, strength, and excellent wear resistance under high-temperature conditions. Detailed Implementation

[0015] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. Example 1

[0016] In this first embodiment, the iron-based alloy of the present invention comprises the following components by mass percentage: Co: 20.0%, Cr: 6.1%, Mo: 10.0%, C: 0.04%, with the balance being Fe and unavoidable impurities.

[0017] In this first embodiment, the method for preparing iron-based alloy rods of the present invention includes the following steps: Step 1: According to the mass percentages of Co, Cr, Mo, Fe, and C in the iron-based alloy, place electrolytic cobalt sheets, metallic chromium blocks, metallic molybdenum bars, pure iron rods, and carbon powder into the crucible of a vacuum induction melting furnace for vacuum induction melting to obtain alloy steel liquid; the outer diameter of the electrolytic cobalt sheets and metallic chromium blocks shall not exceed 50 mm, the diameter of the metallic molybdenum bars and pure iron rods shall not exceed 30 mm and the length shall not exceed 400 mm, and the particle size of the carbon powder shall not exceed 60 mesh and the purity shall not be less than 99.5%; the cleaning time of the vacuum induction melting shall be controlled at 3.0 h and the vacuum degree shall be controlled at below 5 Pa; Step 2: The alloy steel liquid is subjected to high-temperature refining to obtain pure alloy steel liquid; the high-temperature refining temperature is controlled at 1550℃, the vacuum degree is controlled below 0.1Pa, and the time is controlled at 20min; Step 3: Pour the pure alloy steel liquid into the alloy rod mold through the gating system to obtain the alloy casting rod; the pouring temperature is controlled at 1490℃, the vacuum degree is controlled below 5Pa, the pouring time is controlled within 2 minutes, the diameter of the alloy casting rod is controlled at 50mm, and it is taken out of the furnace after cooling for 5 minutes. Step 4: Cut and grind the alloy casting rod to obtain the iron-based alloy rod; the cutting includes cutting the rod head and rod tail, with a length of not less than 10mm cut off at each end; the grinding includes grinding the rod head, rod tail and rod body.

[0018] Testing revealed that the Co-Cr-Mo-Fe-C alloy rod prepared in Example 1 contained 20 ppm of oxygen, had a room temperature hardness of 65 HRC, and an impact toughness (U-notch) of 4.0 J / cm². Example 2

[0019] In this second embodiment, the iron-based alloy of the present invention comprises the following components by mass percentage: Co: 20.0%, Cr: 5.9%, Mo: 10.0%, C: 0.02%, with the balance being Fe and unavoidable impurities.

[0020] In this second embodiment, the method for preparing iron-based alloy rods of the present invention includes the following steps: Step 1: According to the mass percentages of Co, Cr, Mo, Fe, and C in the iron-based alloy, place electrolytic cobalt sheets, metallic chromium blocks, metallic molybdenum bars, pure iron rods, and carbon powder into the crucible of a vacuum induction melting furnace for vacuum induction melting to obtain alloy steel liquid; the outer diameter of the electrolytic cobalt sheets and metallic chromium blocks shall not exceed 50 mm, the diameter of the metallic molybdenum bars and pure iron rods shall not exceed 30 mm and the length shall not exceed 400 mm, and the particle size of the carbon powder shall not exceed 60 mesh and the mass purity shall not be less than 99.5%; the cleaning time of the vacuum induction melting shall be controlled at 4.0 h and the vacuum degree shall be controlled at below 5 Pa; Step 2: The alloy steel liquid is subjected to high-temperature refining to obtain pure alloy steel liquid; the high-temperature refining temperature is controlled at 1600℃, the vacuum degree is controlled below 0.1Pa, and the time is controlled at 40min; Step 3: Pour the pure alloy steel liquid into the alloy rod mold through the gating system to obtain the alloy casting rod; the pouring temperature is controlled at 1500℃, the vacuum degree is controlled below 5Pa, the pouring time is controlled within 2 minutes, the diameter of the alloy casting rod is controlled at 150mm, and it is taken out of the furnace after cooling for 5 minutes. Step 4: Cut and grind the alloy casting rod to obtain the iron-based alloy rod; the cutting includes cutting the rod head and rod tail, with a length of not less than 10mm cut off at each end; the grinding includes grinding the rod head, rod tail and rod body.

[0021] Testing revealed that the Co-Cr-Mo-Fe-C alloy rod prepared in Example 2 contained 19.5 ppm of oxygen, had a room temperature hardness of 64.5 HRC, and an impact toughness (U-notch) of 3.9 J / cm². Example 3

[0022] In this third embodiment, the iron-based alloy of the present invention comprises the following components by mass percentage: Co: 20.0%, Cr: 6.1%, Mo: 10.0%, C: 0.03%, with the balance being Fe and unavoidable impurities.

[0023] In this third embodiment, the method for preparing iron-based alloy rods of the present invention includes the following steps: Step 1: According to the mass percentages of Co, Cr, Mo, Fe, and C in the iron-based alloy, place electrolytic cobalt sheets, metallic chromium blocks, metallic molybdenum bars, pure iron rods, and carbon powder into the crucible of a vacuum induction melting furnace for vacuum induction melting to obtain alloy steel liquid; the outer diameter of the electrolytic cobalt sheets and metallic chromium blocks shall not exceed 50 mm, the diameter of the metallic molybdenum bars and pure iron rods shall not exceed 30 mm and the length shall not exceed 400 mm, and the particle size of the carbon powder shall not exceed 60 mesh and the mass purity shall not be less than 99.5%; the cleaning time of the vacuum induction melting shall be controlled at 3.5 h and the vacuum degree shall be controlled at below 5 Pa; Step 2: The alloy steel liquid is subjected to high-temperature refining to obtain pure alloy steel liquid; the high-temperature refining temperature is controlled at 1500℃, the vacuum degree is controlled below 0.1Pa, and the time is controlled at 30min; Step 3: Pour the pure alloy steel liquid into the alloy rod mold through the gating system to obtain the alloy casting rod; the pouring temperature is controlled at 1450℃, the vacuum degree is controlled below 5Pa, the pouring time is controlled within 2 minutes, the diameter of the alloy casting rod is controlled at 100mm, and it is taken out of the furnace after cooling for 5 minutes. Step 4: Cut and grind the alloy casting rod to obtain the iron-based alloy rod; the cutting includes cutting the rod head and rod tail, with a length of not less than 10mm cut off at each end; the grinding includes grinding the rod head, rod tail and rod body.

[0024] According to the test results, the Co-Cr-Mo-Fe-C alloy rod prepared in Example 3 has an oxygen content of 18.5 ppm, a room temperature hardness of 63.5 HRC, and an impact toughness (U-notch) of 3.8 J / cm². Example 4

[0025] In this fourth embodiment, the iron-based alloy of the present invention comprises the following components by mass percentage: Co: 19.5%, Cr: 5.8%, Mo: 9.5%, C: 0.02%, with the balance being Fe and unavoidable impurities.

[0026] In this fourth embodiment, the method for preparing iron-based alloy rods of the present invention includes the following steps: Step 1: According to the mass percentages of Co, Cr, Mo, Fe, and C in the iron-based alloy, place electrolytic cobalt sheets, metallic chromium blocks, metallic molybdenum bars, pure iron rods, and carbon powder into the crucible of a vacuum induction melting furnace for vacuum induction melting to obtain alloy steel liquid; the outer diameter of the electrolytic cobalt sheets and metallic chromium blocks shall not exceed 50 mm, the diameter of the metallic molybdenum bars and pure iron rods shall not exceed 30 mm and the length shall not exceed 400 mm, and the particle size of the carbon powder shall not exceed 60 mesh and the mass purity shall not be less than 99.5%; the cleaning time of the vacuum induction melting shall be controlled at 3 hours and the vacuum degree shall be controlled at below 5 Pa; Step 2: The alloy steel liquid is subjected to high-temperature refining to obtain pure alloy steel liquid; the high-temperature refining temperature is controlled at 1500℃, the vacuum degree is controlled below 0.1Pa, and the time is controlled at 20min; Step 3: Pour the pure alloy steel liquid into the alloy rod mold through the gating system to obtain the alloy casting rod; the pouring temperature is controlled at 1450℃, the vacuum degree is controlled below 5Pa, the pouring time is controlled within 2 minutes, the diameter of the alloy casting rod is controlled at 50mm, and it is taken out of the furnace after cooling for 3 minutes. Step 4: Cut and grind the alloy casting rod to obtain the iron-based alloy rod; the cutting includes cutting the rod head and rod tail, with a length of not less than 10mm cut off at each end; the grinding includes grinding the rod head, rod tail and rod body.

[0027] Testing revealed that the Co-Cr-Mo-Fe-C alloy rod prepared in Example 4 contained 18 ppm of oxygen by mass, had a room temperature hardness of 63 HRC, and an impact toughness (U-notch) of 3.8 J / cm². Example 5

[0028] In this fifth embodiment, the iron-based alloy of the present invention comprises the following components by mass percentage: Co: 20.5%, Cr: 6.2%, Mo: 10.5%, C: 0.05%, with the balance being Fe and unavoidable impurities.

[0029] In this fifth embodiment, the method for preparing iron-based alloy rods of the present invention includes the following steps: Step 1: According to the mass percentages of Co, Cr, Mo, Fe, and C in the iron-based alloy, place electrolytic cobalt sheets, metallic chromium blocks, metallic molybdenum bars, pure iron rods, and carbon powder into the crucible of a vacuum induction melting furnace for vacuum induction melting to obtain alloy steel liquid; the outer diameter of the electrolytic cobalt sheets and metallic chromium blocks shall not exceed 50 mm, the diameter of the metallic molybdenum bars and pure iron rods shall not exceed 30 mm and the length shall not exceed 400 mm, and the particle size of the carbon powder shall not exceed 60 mesh and the mass purity shall not be less than 99.5%; the cleaning time of the vacuum induction melting shall be controlled at 4 hours and the vacuum degree shall be controlled at below 5 Pa; Step 2: The alloy steel liquid is subjected to high-temperature refining to obtain pure alloy steel liquid; the high-temperature refining temperature is controlled at 1600℃, the vacuum degree is controlled below 0.1Pa, and the time is controlled at 40min; Step 3: Pour the pure alloy steel liquid into the alloy rod mold through the gating system to obtain the alloy casting rod; the pouring temperature is controlled at 1500℃, the vacuum degree is controlled below 5Pa, the pouring time is controlled within 2 minutes, the diameter of the alloy casting rod is controlled at 150mm, and it is taken out of the furnace after cooling for 4 minutes. Step 4: Cut and grind the alloy casting rod to obtain the iron-based alloy rod; the cutting includes cutting the rod head and rod tail, with a length of not less than 10mm cut off at each end; the grinding includes grinding the rod head, rod tail and rod body.

[0030] Testing revealed that the Co-Cr-Mo-Fe-C alloy rod prepared in Example 5 contained 19 ppm of oxygen, had a room temperature hardness of 64.5 HRC, and an impact toughness (U-notch) of 3.9 J / cm².

[0031] In the above embodiments, high-temperature wear tests were conducted on the obtained alloy materials. At 800℃ for 100 hours, the wear depth on the material surface was less than 0.05 mm; at -100℃ for 100 hours, the wear depth on the material surface was also less than 0.05 mm. This demonstrates that the iron-based alloy obtained by this invention still exhibits good wear resistance under both low and high temperature conditions.

[0032] Obviously, the above embodiments are merely some, not all, of the embodiments of the present invention. The above embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention. Based on the above embodiments, all other embodiments obtained by those skilled in the art without inventive effort, that is, all modifications, equivalent substitutions, and improvements made within the spirit and principle of this application, fall within the scope of protection claimed by the present invention.

Claims

1. An iron-based alloy, characterized in that, By mass percentage, it includes the following components: Co: 19.5%~20.5%, Cr：5.8%～6.2%， Mo: 9.5%–10.5%, C: >0.01% and ≤0.05%, The balance is Fe and unavoidable impurities.

2. The iron-based alloy according to claim 1, characterized in that, By mass percentage, it includes the following components: Co: 20.0%, Cr：6.1%， Mo: 10.0%, C：0.04%， The balance is Fe and unavoidable impurities.

3. The iron-based alloy according to claim 1, characterized in that, By mass percentage, it includes the following components: Co: 20.0%, Cr：5.9%， Mo: 10.0%, C：0.02%， The balance is Fe and unavoidable impurities.

4. A method for preparing a rod of an iron-based alloy according to any one of claims 1 to 3, characterized in that, Includes the following steps: Step 1: According to the mass percentages of Co, Cr, Mo, Fe, and C in the iron-based alloy, place electrolytic cobalt sheets, metallic chromium blocks, metallic molybdenum bars, pure iron rods, and carbon powder into the crucible of a vacuum induction melting furnace for vacuum induction melting to obtain alloy steel liquid. Step 2: The alloy steel liquid is refined at high temperature to obtain pure alloy steel liquid; Step 3: Pour the pure alloy steel liquid into the alloy rod mold through the gating system to obtain the alloy casting rod; Step 4: Cut and grind the alloy casting rod to obtain the iron-based alloy rod.

5. The method for preparing iron-based alloy rods according to claim 4, characterized in that, In step 1, the electrolytic cobalt sheet and the metallic chromium block have an external diameter of no more than 50 mm, the metallic molybdenum strip and the pure iron rod have a diameter of no more than 30 mm and a length of no more than 400 mm, and the carbon powder has a particle size of no more than 60 mesh and a purity of no less than 99.5%.

6. The method for preparing iron-based alloy rods according to claim 4, characterized in that, In step 1, the clearing time of the vacuum induction melting is controlled at 3.0-4.0 h and the vacuum degree is controlled at below 5 Pa.

7. The method for preparing iron-based alloy rods according to claim 4, characterized in that, In step 2, the high-temperature refining temperature is controlled at 1500-1600℃, the vacuum degree is controlled below 0.1Pa, and the time is controlled at 20-40min.

8. The method for preparing iron-based alloy rods according to claim 4, characterized in that, In step 3, the temperature of the steel casting is controlled at 1450-1500℃, the vacuum degree is controlled below 5Pa, the casting time is controlled within 2 minutes, the diameter of the alloy casting rod is controlled at 50-150mm, and it is taken out of the furnace after cooling for 3-5 minutes.

9. The method for preparing iron-based alloy rods according to claim 4, characterized in that, In step 4, the cutting includes cutting the rod head and the rod tail, with each head having a cut length of not less than 10mm, and the grinding includes grinding the rod head, the rod tail, and the rod body.