A seamless steel pipe processing process

Abstract

The invention belongs to the technical field of steel processing and discloses a seamless steel pipe processing process, which comprises the steps of stretching by hot rolling, spraying a treatment liquid on the surface of the steel during the stretching process, then extrusion welding, removing the weld ribs after welding, spraying a secondary treatment liquid on the inner and outer surfaces of the steel pipe during the process, and then sending the steel pipe to an electric furnace and heating it at a temperature of 600-700°C for a period of time and then cooling it, and then taking it out of the electric furnace and cooling it to room temperature. The invention sprays the steel plate with treatment liquids of different proportions for multiple times during the steel pipe production process, forms a protective film on the surface of the rod steel by the treatment liquid, enhances the corrosion resistance and wear resistance, and enhances the yield resistance and tensile strength of the steel by high temperature treatment.

Description

Technical Field

[0001] The invention belongs to the technical field of steel material processing, and in particular relates to a seamless steel pipe processing process. Background Art

[0002] Steel oxidation is also known as bluing. The bluing process has the advantages of simple equipment, low investment, low cost, and quick results. It has been widely used in mechanical manufacturing and other fields. However, the yield strength and tensile strength of steel parts treated by traditional steel oxidation process are low. Therefore, a steel oxidation treatment process that can enhance the yield strength and tensile strength of steel parts is needed. Summary of the invention

[0003] The purpose of the present invention is to provide a seamless steel pipe processing process in which the steel plate is sprayed with treatment liquids of different proportions for multiple times during the steel pipe production process, a protective film is formed on the surface of the rod steel by the treatment liquid to enhance the corrosion resistance and wear resistance, and the yield resistance and tensile strength of the steel are enhanced by high-temperature treatment.

[0004] Based on the above purpose, the present invention adopts the following technical scheme: a seamless steel pipe processing process, the seamless steel pipe processing process is: hot coils are split, and then sent to the processing workshop through a feeding mechanism, the steel plate is extruded and stretched, and then made into a steel pipe through high-frequency welding, and then the weld ribs are removed by internal and external scrapers, and finally cut, heated in an electric furnace and naturally cooled to room temperature by air; specifically comprising the following steps:

[0005] The hot coil is stretched, and during the stretching process, a treatment liquid is sprayed on the surface of the steel;

[0006] The welded steel pipe is de-welded, and secondary treatment liquid is sprayed on the inner and outer surfaces of the steel pipe during the de-welding process; the cut steel pipe is sent to an electric furnace and heated at 600-700℃ for 9-10 hours, then left to stand for 2-3 hours and taken out when the temperature drops to 300℃.

[0007] Preferably, the primary treatment liquid consists of water and nitrite, wherein the mass ratio of nitrite is 0.8% to 1.2%.

[0008] Preferably, the secondary treatment liquid consists of water and nitrite, wherein the mass ratio of nitrite is 30% to 36%.

[0009] Preferably, a treatment liquid is composed of nitrite, trisodium phosphate and water, wherein the mass ratio of nitrite, trisodium phosphate and water is 0.2%-0.5%, 0.3%-0.8%, 98.7%-99.5%; preferably, the ratio of nitrite, trisodium phosphate and water is 0.32%:0.48%:99.2%.

[0010] Preferably, the secondary treatment liquid is composed of nitrite, trisodium phosphate and water, wherein the mass ratio of nitrite, trisodium phosphate and water is 30%-36%, 0.4%-0.9%, and 63.1%-69.6%; the preferred ratio of nitrite, trisodium phosphate and water is 32%:0.48%:67.52%.

[0011] Preferably, a treatment liquid is composed of nitrite, sodium polyphosphate and water, and the weight percentages of each component are 0.3% to 0.6%, 0.4% to 1%, and 99.3% to 98.4%, respectively. The preferred ratio of nitrite, sodium polyphosphate and water is 0.28%:0.52%:99.2%.

[0012] Preferably, the secondary treatment liquid is composed of nitrite, sodium polyphosphate and water, and the weight percentages of each component are 30% to 36%, 0.3% to 0.9%, and 63.1% to 69.7%, respectively; the preferred ratio of nitrite, sodium polyphosphate and water is 35%:0.5%:64.5%.

[0013] Preferably, a treatment liquid is composed of cerium nitrate, lanthanum nitrate, sodium molybdate, nitrite and water, wherein the mass percentages of cerium nitrate, lanthanum nitrate, sodium molybdate, nitrite and water are 0.4% to 0.7%, 0.8% to 1.4%, 0.8% to 1.4%, 18% to 25% and 71.5% to 80%; preferably, the ratio of cerium nitrate, lanthanum nitrate, sodium molybdate, nitrite and water is 0.6%:1.2%:1.2%:25%:72%.

[0014] Preferably, the secondary treatment liquid is composed of cerium nitrate, lanthanum nitrate, sodium molybdate, nitrite and water, wherein the mass percentages of cerium nitrate, lanthanum nitrate, sodium molybdate, nitrite and water are 0.4% to 0.7%, 0.8% to 1.4%, 0.8% to 1.4%, 30% to 36% and 60.5% to 68%; preferably, the ratio of cerium nitrate, lanthanum nitrate, sodium molybdate, nitrite and water is 0.6%:1.2%:1.2%:25%:72%.

[0015] Preferably, the temperature of the secondary treatment liquid during spraying is 550-750 degrees Celsius.

[0016] The present invention has the following beneficial effects over the prior art: the present invention uses a sodium nitrate solution at room temperature to spray during the steel stretching process, thereby removing rust from the steel and oxidizing the steel at the same time, forming an oxide film on the surface of the steel to enhance corrosion resistance, and then after the steel is de-welded, the steel pipe is sprayed again at high temperature to enhance the yield resistance and tensile strength of the steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the process flow of the present invention.

[0018] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0019] like Figure 1 A seamless steel pipe processing process is shown, the seamless steel pipe processing process is: the hot coil is divided, and then sent to the processing workshop through the feeding mechanism, the steel plate is extruded and stretched, and then made into a steel pipe through high-frequency welding, and then the weld ribs are removed by internal and external scrapers, and finally cut, heated in an electric furnace and naturally cooled to room temperature by air; specifically, the following steps are included:

[0020] The hot coil is stretched, and during the stretching process, a treatment liquid is sprayed on the surface of the steel;

[0021] The welded steel pipe is de-welded, and secondary treatment liquid is sprayed on the inner and outer surfaces of the steel pipe during the de-welding process; the cut steel pipe is sent to an electric furnace and heated at 600-700℃ for 9-10 hours, then left to stand for 2-3 hours and taken out when the temperature drops to 300℃.

[0022] The primary treatment liquid consists of water and nitrite, wherein the mass ratio of the nitrite is 0.8% to 1.2%.

[0023] The secondary treatment liquid consists of water and nitrite, wherein the mass ratio of the nitrite is 30% to 36%.

[0024] In one embodiment, the hot coil is split and then sent to the stretching part for stretching through a feeding mechanism. During the stretching process, a treatment liquid is sprayed on the surface of the steel part at room temperature or with cold water. After the stretching treatment is completed, it is extruded and welded into a steel pipe, and then the weld ribs are removed from the inside and outside of the steel pipe. After the weld ribs are removed, a secondary treatment liquid is sprayed on the inside and outside of the steel pipe at a temperature of 650 degrees Celsius. The secondary treatment liquid is prepared with pure water and nitrite, and the mass specific gravity of the nitrite is 30%, 32% or 35%; then the steel pipe is cut, and the cut steel pipe is sent to an electric furnace for heating, and the heating is controlled to be from room temperature to 600-700 degrees within 9-10 hours. When the power is turned off at 700 degrees, the heating is stopped, and then it is left to stand for 2-3 hours to drop to about 300 degrees and then taken out of the furnace, and naturally cooled to room temperature in the air. Example

[0025] A seamless steel pipe processing process, compared with Example 1, a processing liquid consists of nitrite, trisodium phosphate and water, wherein the mass ratio of nitrite, trisodium phosphate and water is 0.2%-0.5%, 0.3%-0.8%, 98.7%-99.5%; the preferred ratio of nitrite, trisodium phosphate and water is 0.32%:0.48%:99.2%.

[0026] The secondary treatment liquid is composed of nitrite, trisodium phosphate and water, wherein the mass ratio of nitrite, trisodium phosphate and water is 30%-36%, 0.4%-0.9% and 63.1%-69.6%; the preferred ratio of nitrite, trisodium phosphate and water is 32%:0.48%:67.52%.

[0027] In one embodiment, the hot coil is split and then sent to the stretching part for stretching through a feeding mechanism. During the stretching process, a treatment liquid is sprayed on the surface of the steel part at room temperature or with cold water. After the stretching treatment is completed, the steel pipe is made into a steel pipe through extrusion and welding, and then the weld ribs are removed from the inside and outside of the steel pipe. After the weld ribs are removed, a secondary treatment liquid is sprayed on the inside and outside of the steel pipe at a temperature of 650 degrees Celsius; then the steel pipe is cut, and the cut steel pipe is sent to an electric furnace for heating, and the heating is controlled from room temperature to 600-700 degrees within 9-10 hours. When the power is turned off at 700 degrees, the heating is stopped, and then it is left to stand for 2-3 hours to cool to about 300 degrees and then taken out of the furnace, and naturally cooled to room temperature in the air. The remaining settings and operations are the same as those in Example 1.

[0028] Example

[0029] A seamless steel pipe processing process, compared with Example 1, a processing liquid consists of nitrite, sodium polyphosphate and water, the weight percentage of each component is 0.3% to 0.6%, 0.4% to 1%, 99.3% to 98.4%, and the preferred ratio of nitrite, sodium polyphosphate and water is 0.28%:0.52%:99.2%.

[0030] The secondary treatment liquid is composed of nitrite, sodium polyphosphate and water, and the weight percentages of the components are 30%-36%, 0.3%-0.9%, and 63.1%-69.7% respectively; the preferred ratio of nitrite, sodium polyphosphate and water is 35%:0.5%:64.5%.

[0031] In one embodiment, the hot coil is split and then sent to the stretching part for stretching through a feeding mechanism. During the stretching process, a treatment liquid is sprayed on the surface of the steel part at room temperature or with cold water. After the stretching treatment is completed, the steel pipe is made into a steel pipe through extrusion and welding, and then the weld ribs are removed from the inside and outside of the steel pipe. After the weld ribs are removed, a secondary treatment liquid is sprayed on the inside and outside of the steel pipe at a temperature of 650 degrees Celsius; then the steel pipe is cut, and the cut steel pipe is sent to an electric furnace for heating, and the heating is controlled from room temperature to 600-700 degrees within 9-10 hours. When the power is turned off at 700 degrees, the heating is stopped, and then it is left to stand for 2-3 hours to cool to about 300 degrees and then taken out of the furnace, and naturally cooled to room temperature in the air. The remaining settings and operations are the same as those in Example 1.

[0032] Example

[0033] A seamless steel pipe processing process, compared with Example 1, a processing liquid consists of cerium nitrate, lanthanum nitrate, sodium molybdate, nitrite and water, wherein the mass percentages of cerium nitrate, lanthanum nitrate, sodium molybdate, nitrite and water are 0.4% to 0.7%, 0.8% to 1.4%, 0.8% to 1.4%, 18% to 25% and 71.5% to 80%; the preferred ratio of cerium nitrate, lanthanum nitrate, sodium molybdate, nitrite and water is 0.6%:1.2%:1.2%:25%:72%.

[0034] The secondary treatment liquid is composed of cerium nitrate, lanthanum nitrate, sodium molybdate, nitrite and water, wherein the mass percentages of cerium nitrate, lanthanum nitrate, sodium molybdate, nitrite and water are 0.4%-0.7%, 0.8%-1.4%, 0.8%-1.4%, 30%-36% and 60.5%-68%; the preferred ratio of cerium nitrate, lanthanum nitrate, sodium molybdate, nitrite and water is 0.6%:1.2%:1.2%:25%:72%.

[0035] In one embodiment, the hot coil is split and then sent to the stretching part for stretching through a feeding mechanism. During the stretching process, a treatment liquid is sprayed on the surface of the steel part at room temperature or with cold water. After the stretching treatment is completed, the steel pipe is made into a steel pipe through extrusion and welding, and then the weld ribs are removed from the inside and outside of the steel pipe. After the weld ribs are removed, a secondary treatment liquid is sprayed on the inside and outside of the steel pipe at a temperature of 650 degrees Celsius; then the steel pipe is cut, and the cut steel pipe is sent to an electric furnace for heating, and the heating is controlled from room temperature to 600-700 degrees within 9-10 hours. When the power is turned off at 700 degrees, the heating is stopped, and then it is left to stand for 2-3 hours to cool to about 300 degrees and then taken out of the furnace, and naturally cooled to room temperature in the air. The remaining settings and operations are the same as those in Example 1.

[0036] The above are only preferred embodiments of the present invention, which are only used to illustrate the scheme and effect of the present invention and cannot be considered to limit the scope of implementation of the present invention. It should be pointed out that for ordinary technicians in this technical field, several changes and improvements can be made without departing from the concept of the present invention, which should still fall within the scope of the patent coverage of the present invention.

Claims

1. A seamless steel pipe processing process, characterized in that: The seamless steel pipe processing process is as follows: the hot coil is split, and then sent to the processing workshop through the feeding mechanism, the steel plate is extruded and stretched, and then made into a steel pipe through high-frequency welding, and then the weld ribs are removed by internal and external scrapers, and finally cut, heated in an electric furnace and naturally cooled to room temperature by air; The specific steps include: The steel plate is stretched, and during the stretching process, a treatment liquid is sprayed on the surface of the steel plate; Remove the weld ribs from the welded steel pipe, and spray the secondary treatment liquid on the inner and outer surfaces of the steel pipe after removing the weld ribs; The cut steel pipe is sent to an electric furnace and heated at 600-700℃ for 9-10 hours, then left to stand for 2-3 hours until the temperature drops to 300℃ and then taken out; The primary treatment liquid is composed of water and nitrite, wherein the mass percentage of nitrite is 0.8% to 1.2%; the secondary treatment liquid is composed of water and nitrite, wherein the mass percentage of nitrite is 30% to 36%; the temperature of the secondary treatment liquid during spraying is 550 to 750 degrees Celsius.

2. The seamless steel pipe processing process according to claim 1, characterized in that: The primary treatment liquid is composed of nitrite, trisodium phosphate and water, wherein the mass percentages of nitrite, trisodium phosphate and water are 0.2% to 0.5%, 0.3% to 0.8% and 98.7% to 99.5% respectively.

3. The seamless steel pipe processing process according to claim 2, characterized in that: The secondary treatment liquid is composed of nitrite, trisodium phosphate and water, wherein the mass percentages of nitrite, trisodium phosphate and water are 30% to 36%, 0.4% to 0.9% and 63.1% to 69.6%.

4. The seamless steel pipe processing process according to claim 1, characterized in that: The primary treatment liquid is composed of nitrite, sodium polyphosphate and water, and the weight percentages of the components are 0.3% to 0.6%, 0.4% to 1%, and 99.3% to 98.4%, respectively.

5. The seamless steel pipe processing process according to claim 4, characterized in that: The secondary treatment liquid is composed of nitrite, sodium polyphosphate and water, and the weight percentages of the components are 30% to 36%, 0.3% to 0.9%, and 63.1% to 69.7%, respectively.

6. The seamless steel pipe processing process according to claim 1, characterized in that: The primary treatment liquid is composed of cerium nitrate, lanthanum nitrate, sodium molybdate, nitrite and water, wherein the mass percentages of cerium nitrate, lanthanum nitrate, sodium molybdate, nitrite and water are 0.4% to 0.7%, 0.8% to 1.4%, 0.8% to 1.4%, 18% to 25% and 71.5% to 80%.

7. The seamless steel pipe processing process according to claim 6, characterized in that: The secondary treatment liquid is composed of cerium nitrate, lanthanum nitrate, sodium molybdate, nitrite and water, wherein the mass percentages of cerium nitrate, lanthanum nitrate, sodium molybdate, nitrite and water are 0.4%-0.7%, 0.8%-1.4%, 0.8%-1.4%, 30%-36% and 60.5%-68%.

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