Detailed Description
The present invention is described in further detail below.
Example 1
A preparation method of powder metallurgy high-speed steel comprises the following steps:
(1) Sieving M42 high-speed steel powder into powder with different particle size ranges of more than 275 microns, 225-275 microns, 200-250 microns, 175-225 microns, 150-200 microns, 125-175 microns, 75-125 microns and less than 100 microns;
(2) Sequentially arranging the powder in a composite sheath formed by concentrically sheathing sheaths with diameters of 100, 150, 200, 250, 300, 350, 400 and 450mm from outside to inside according to the order of the particle size range from large to small, and then removing the inner sheath and only keeping the outermost sheath;
(3) Vibrating the composite sheath for degassing, and then circularly performing degassing treatment of vacuumizing and nitrogen filling for 4 times;
(4) Hot isostatic pressing the sheath at 1000 ℃, wherein the pressure is 80MPa, and the time is 6h;
(5) Rapidly heating the hot isostatic pressing steel ingot to 1050 ℃ at a speed of 50 ℃/min, heating for 4h, then heating to 1120 ℃ by utilizing induction heating, and heating for 2h;
(6) Carrying out discontinuous progressive radial forging on the annealed steel ingot, wherein the forging frequency is 90 times/min, and the forging reduction per minute is 10mm;
(7) And (3) heating the billet steel to 700 ℃ by induction heating, preserving heat for 2h, then heating to 1180 ℃, preserving heat for 15min, and quenching to obtain the high-speed steel.
In all drawings of the present application, (a) is a surface layer and (b) is an inner layer. As can be seen from FIG. 1, the surface layer has an average grain size of about 4.2 μm, the carbides have an average grain size of about 4.9 μm, the inner layer has an average grain size of about 10.2 μm, and the carbides have an average grain size of about 2.7 μm, and a gradient structure is formed in which the carbide size gradually decreases from the surface layer to the inner layer and the grain size gradually increases from the surface to the inside.
Example 2
A preparation method of powder metallurgy high-speed steel comprises the following steps:
(1) Sieving M42 high-speed steel powder into powder with different particle size ranges of more than 275 microns, 225-275 microns, 200-250 microns, 175-225 microns, 150-200 microns, 125-175 microns, 75-125 microns, less than 100 microns and the like;
(2) Sequentially arranging the powder in a composite sheath formed by concentrically sheathing sheaths with the diameters of 100 mm, 250 mm, 400 mm, 550 mm, 700 mm, 850 mm, 1000 mm and 1150mm from outside to inside according to the order of the particle size range from large to small, removing the sheath at the inner layer, and only reserving the sheath at the outermost layer;
(3) Vibrating the composite sheath for degassing, and then circularly performing degassing treatment of vacuumizing and nitrogen filling for 5 times;
(4) Hot isostatic pressing the ladle sleeve at 1100 ℃, wherein the pressure is 120MPa, and the time is 2h;
(5) Rapidly heating the hot isostatic pressing steel ingot to 1120 ℃ at a speed of 15 ℃/min, heating for 2h, then heating to 1180 ℃ by utilizing induction heating, and heating for 1h;
(6) Carrying out discontinuous progressive radial forging on the annealed steel ingot, wherein the forging frequency is 150 times/min, and the forging reduction per minute is 3mm;
(7) And (3) heating the steel billet to 900 ℃ by induction heating, preserving heat for 0.5h, then heating to 1220 ℃, preserving heat for 5min, and quenching to obtain the high-speed steel.
As can be seen from FIG. 2, the average size of the grains of the surface layer is about 3.9 μm, the average size of the carbides is about 4.7 μm, the average size of the grains of the inner layer is about 10.5 μm, the average size of the carbides is about 2.3 μm, and a gradient structure is formed in which the size of the carbides decreases from the surface layer to the inner layer and the size of the grains increases from the surface to the inner portion
Example 3
A preparation method of powder metallurgy high-speed steel comprises the following steps:
(1) Sieving TPM558 high-speed steel powder into powder with different particle size ranges of more than 275 microns, 225-275 microns, 200-250 microns, 175-225 microns, 150-200 microns, 125-175 microns, 75-125 microns and less than 100 microns;
(2) Sequentially arranging the powder in a composite sheath formed by concentrically sheathing sheaths with diameters of 100, 200, 300, 400, 500, 600, 700 and 800mm from outside to inside according to the order of the particle size range from large to small, removing the inner sheath and only keeping the outermost sheath;
(3) Vibrating the composite sheath for degassing, and then circularly performing degassing treatment of vacuumizing and nitrogen filling for 3 times;
(4) Hot isostatic pressing the sheath at 1050 ℃, wherein the pressure is 100MPa, and the time is 4h;
(5) Rapidly heating the hot isostatic pressing steel ingot to 1080 ℃ at a speed of 15 ℃/min, heating for 3h, then heating to 1160 ℃ by utilizing induction heating, and heating for 1h;
(6) Carrying out discontinuous progressive radial forging on the annealed steel ingot, wherein the forging frequency is 100 times/min, and the forging reduction per minute is 8mm;
(7) And (3) heating the steel billet to 800 ℃ by induction heating, preserving heat for 1h, then heating to 1220 ℃, preserving heat for 5min, and quenching to obtain the high-speed steel.
As can be seen from FIG. 3, the average size of the grains of the surface layer is about 3.8 μm, the average size of the carbides is about 5.1 μm, the average size of the grains of the inner layer is about 9.7 μm, and the average size of the carbides is about 2.4 μm, forming a gradient structure in which the size of the carbides decreases from the surface layer to the inner layer and the size of the grains increases from the surface to the inside.
Example 4
A preparation method of powder metallurgy high-speed steel comprises the following steps:
(1) Sieving TPM558 high speed steel powder into powder of 275-275 micron size, 225-275 micron size, 200-250 micron size, 175-225 micron size, 150-200 micron size, 125-175 micron size, 75-125 micron size and below 100 micron size;
(2) Sequentially arranging the powder in a composite sheath formed by concentrically sheathing sheaths with diameters of 100 mm, 200 mm, 300 mm, 400 mm, 500 mm, 600 mm, 700 mm and 800mm from outside to inside according to the order of the particle size range from large to small, removing the sheath at the inner layer, and only reserving the sheath at the outermost layer;
(3) Vibrating the composite sheath for degassing, and then circularly performing degassing treatment of vacuumizing and nitrogen filling for 5 times;
(4) Hot isostatic pressing the clad at 1050 ℃, wherein the pressure is 110MPa, and the time is 5h;
(5) Rapidly heating the hot isostatic pressing steel ingot to 1100 ℃ at a speed of 15 ℃/min for 3h, then heating to 1170 ℃ by using induction heating, and heating for 1h;
(6) Carrying out discontinuous progressive radial forging on the annealed steel ingot, wherein the forging frequency is 120 times/min, and the forging reduction per minute is 6mm;
(7) And (3) heating the steel billet to 800 ℃ by induction heating, preserving heat for 1h, then heating to 1200 ℃, preserving heat for 10min, and quenching to obtain the high-speed steel.
As can be seen from FIG. 4, the surface layer has an average grain size of about 4.3 μm, the carbides have an average grain size of about 5.1 μm, the inner layer has an average grain size of about 11.5 μm, and the carbides have an average grain size of about 2.4 μm, and a gradient structure is formed in which the carbide size gradually decreases from the surface layer to the inner layer and the grain size gradually increases from the surface to the inside.
Example 5
A preparation method of powder metallurgy high-speed steel comprises the following steps:
(1) Screening TPM380 high speed steel powder into powder of 275 micron over, 225-275 micron, 200-250 micron, 175-225 micron, 150-200 micron, 125-175 micron, 75-125 micron and 100 micron below different grain size range;
(2) Sequentially arranging the powder in a composite sheath formed by concentrically sheathing sheaths with diameters of 100, 200, 300, 400, 500, 600, 700 and 800mm from outside to inside according to the order of the particle size range from large to small, removing the inner sheath and only keeping the outermost sheath;
(3) Vibrating the composite sheath for degassing, and then circularly performing degassing treatment of vacuumizing and nitrogen filling for 3 times;
(4) Hot isostatic pressing the sheath at 1050 ℃, wherein the pressure is 110MPa, and the time is 3h;
(5) Rapidly heating the hot isostatic pressing steel ingot to 1100 ℃ at a speed of 15 ℃/min, heating for 2h, then heating to 1180 ℃ by utilizing induction heating, and heating for 1h;
(6) Carrying out discontinuous progressive radial forging on the annealed steel ingot, wherein the forging frequency is 110 times/min, and the forging reduction per minute is 7mm;
(7) And (3) heating the billet steel to 800 ℃ by induction heating, preserving heat for 1h, then heating to 1190 ℃, preserving heat for 12min, and quenching to obtain the high-speed steel.
As can be seen from FIG. 5, the surface layer has an average grain size of about 4.5 μm, the carbides have an average grain size of about 4.6 μm, the inner layer has an average grain size of about 10.9 μm, and the carbides have an average grain size of about 2.5 μm, and a gradient structure is formed in which the carbide size gradually decreases from the surface layer to the inner layer and the grain size gradually increases from the surface to the inside.
Example 6
A preparation method of powder metallurgy high-speed steel comprises the following steps:
(1) Sieving M42 high-speed steel powder into powder with different particle size ranges of more than 275 microns, 225-275 microns, 200-250 microns, 175-225 microns, 150-200 microns, 125-175 microns, 75-125 microns and less than 100 microns;
(2) Sequentially arranging the powder in a composite sheath formed by concentrically sheathing sheaths with diameters of 100 mm, 200 mm, 300 mm, 400 mm, 500 mm, 600 mm, 700 mm and 800mm from outside to inside according to the order of the particle size range from large to small, removing the sheath at the inner layer, and only reserving the sheath at the outermost layer;
(3) Hot isostatic pressing the clad at 1050 ℃, wherein the pressure is 100MPa, and the time is 4h;
(4) Rapidly heating the hot isostatic pressing steel ingot to 1050 ℃ at a speed of 15 ℃/min, heating for 4h, then heating to 1120 ℃ by utilizing induction heating, and heating for 2h;
(5) Carrying out discontinuous progressive radial forging on the annealed steel ingot, wherein the forging frequency is 100 times/min, and the forging reduction per minute is 7mm;
(6) And (3) heating the steel billet to 800 ℃ by induction heating, preserving heat for 1h, then heating to 1180 ℃, preserving heat for 15min, and quenching to obtain the high-speed steel.
As can be seen from FIG. 6, the surface layer crystal grains have an average size of about 3.9 μm, the carbides have an average size of about 5.1 μm, the inner layer crystal grains have an average size of about 9.8 μm, and the carbides have an average size of about 2.3 μm, and a gradient structure is formed in which the carbide size gradually decreases from the surface layer to the inner layer and the crystal grain size gradually increases from the surface to the inside.
Comparative example 1
A preparation method of powder metallurgy high-speed steel comprises the following steps:
(1) Sieving the TFM5610 high-speed steel powder into powder with different particle size ranges of more than 275 microns, 225-275 microns, 200-250 microns, 175-225 microns, 150-200 microns, 125-175 microns, 75-125 microns and less than 100 microns;
(2) Sequentially arranging the powder in a composite sheath formed by concentrically sheathing sheaths with diameters of 100 mm, 200 mm, 300 mm, 400 mm, 500 mm, 600 mm, 700 mm and 800mm from outside to inside according to the order of the particle size range from large to small, removing the sheath at the inner layer, and only reserving the sheath at the outermost layer;
(3) Vibrating the composite sheath for degassing, and then circularly performing degassing treatment of vacuumizing and nitrogen filling for 4 times;
(4) Hot isostatic pressing the clad at 1050 ℃, wherein the pressure is 100MPa, and the time is 4h;
(5) Slowly heating the hot isostatic pressing steel ingot to 1050 ℃ at the speed of 5 ℃/min, heating for 4h, then heating to 1120 ℃ by utilizing induction heating, and heating for 2h;
(6) Carrying out discontinuous progressive radial forging on the annealed steel ingot, wherein the forging frequency is 100 times/min, and the forging reduction per minute is 7mm;
(7) And (3) heating the steel billet to 800 ℃ by induction heating, preserving heat for 1h, then heating to 1180 ℃, preserving heat for 15min, and quenching to obtain the high-speed steel.
As can be seen from FIG. 7, in this comparative example, since the temperature increase rate of the inner layer spheroidizing annealing in step (5) was slow, the spheroidizing effect of the carbide of the inner layer was not good, and a carbide gradient was not obtained.
Comparative example 2
A preparation method of powder metallurgy high-speed steel comprises the following steps:
(1) Sieving M42 high-speed steel powder into powder with different particle size ranges of more than 275 microns, 225-275 microns, 200-250 microns, 175-225 microns, 150-200 microns, 125-175 microns, 75-125 microns and less than 100 microns;
(2) Sequentially arranging the powder in a composite sheath formed by concentrically sheathing sheaths with diameters of 100 mm, 200 mm, 300 mm, 400 mm, 500 mm, 600 mm, 700 mm and 800mm from outside to inside according to the order of the particle size range from large to small, removing the sheath at the inner layer, and only reserving the sheath at the outermost layer;
(3) Vibrating the composite sheath for degassing, and then circularly performing degassing treatment of vacuumizing and nitrogen filling for 4 times;
(4) Hot isostatic pressing the sheath at 1050 ℃, wherein the pressure is 100MPa, and the time is 4h;
(5) Rapidly heating the hot isostatic pressing steel ingot to 1120 ℃ at a speed of 15 ℃/min, and heating for 4h;
(6) Carrying out discontinuous progressive radial forging on the annealed steel ingot, wherein the forging frequency is 100 times/min, and the forging reduction per minute is 7mm;
(7) And (3) heating the steel billet to 800 ℃ by induction heating, preserving heat for 1h, then heating to 1180 ℃, preserving heat for 15min, and quenching to obtain the high-speed steel.
As can be seen from fig. 8, in the comparative example, without the step annealing, the carbides of the surface layer and the inner layer are similar in size, and a carbide gradient is not obtained.
Comparative example 3
A preparation method of powder metallurgy high-speed steel comprises the following steps:
(1) Sieving M42 high-speed steel powder into powder with different particle size ranges of more than 275 microns, 225-275 microns, 200-250 microns, 175-225 microns, 150-200 microns, 125-175 microns, 75-125 microns and less than 100 microns;
(2) Sequentially arranging the powder in a composite sheath formed by concentrically sheathing sheaths with diameters of 100 mm, 200 mm, 300 mm, 400 mm, 500 mm, 600 mm, 700 mm and 800mm from outside to inside according to the order of the particle size range from large to small, removing the sheath at the inner layer, and only reserving the sheath at the outermost layer;
(3) Vibrating the composite sheath for degassing, and then circularly performing degassing treatment of vacuumizing and nitrogen filling for 4 times;
(4) Hot isostatic pressing the sheath at 1050 ℃, wherein the pressure is 100MPa, and the time is 4h;
(5) Rapidly heating the hot isostatic pressing steel ingot to 1050 ℃ at a speed of 15 ℃/min, heating for 4h, then heating to 1120 ℃ by utilizing induction heating, and heating for 2h;
(6) Carrying out conventional forging on the annealed steel ingot;
(7) And (3) heating the steel billet to 800 ℃ by induction heating, preserving heat for 1h, then heating to 1180 ℃, preserving heat for 15min, and quenching to obtain the high-speed steel.
As can be seen from fig. 9, in this comparative example, in which the conventional forging method was used, the surface layer and the inner layer had similar grain sizes, and no grain gradient was obtained.
Comparative example 4
A preparation method of powder metallurgy high-speed steel comprises the following steps:
(1) Sieving M42 high-speed steel powder into powder with different particle size ranges of more than 275 microns, 225-275 microns, 200-250 microns, 175-225 microns, 150-200 microns, 125-175 microns, 75-125 microns and less than 100 microns;
(2) Sequentially arranging the powder in a composite sheath formed by concentrically sheathing sheaths with diameters of 100, 200, 300, 400, 500, 600, 700 and 800mm from outside to inside according to the order of the particle size range from large to small, removing the inner sheath and only keeping the outermost sheath;
(3) Vibrating the composite sheath for degassing, and then circularly performing degassing treatment of vacuumizing and nitrogen filling for 4 times;
(4) Hot isostatic pressing the clad at 1050 ℃, wherein the pressure is 100MPa, and the time is 4h;
(5) Rapidly heating the hot isostatic pressing steel ingot to 1050 ℃ at a speed of 15 ℃/min, heating for 4h, then heating to 1120 ℃ by utilizing induction heating, and heating for 2h;
(6) Carrying out discontinuous progressive radial forging on the annealed steel ingot, wherein the forging frequency is 100 times/min, and the forging reduction per minute is 7mm;
(7) And (3) quenching the steel billet by adopting a conventional salt bath quenching process after heat preservation for 10min at 1200 ℃ to obtain the high-speed steel.
As can be seen from fig. 10, in the present comparative example, using the conventional quenching method, the surface layer and the inner layer have grain sizes close to each other, and no grain gradient is obtained.