阅读说明：本技术 一种干壁钉钢半成品钢丝的退火工艺 (Annealing process of drywall nail steel semi-finished steel wire ) 是由 高协清 苏振伟 吴春树 左锦中 林俊 万文华 于 2021-08-18 设计创作，主要内容包括：本发明涉及一种干壁钉钢半成品钢丝的退火工艺,使用辊底式连续退火炉来对干壁钉钢半成品钢丝进行全连续退火生产,辊底式连续退火炉进出端都配置真空锁气室,同时使用RX和氮气作为半成品钢丝的保护气体,产品表面脱碳质量可以保证,所以可以采用高加热温度、快辊速的工艺思想。本发明根据辊底式连续退火炉各工艺段长度参数合理设计辊速,平衡加热温度和加热时间、缓冷温度和缓冷时间,既满足了产品质量要求,又提高了产量、降低了综合生产成本。(The invention relates to an annealing process of a drywall nail steel semi-finished steel wire, which uses a roller bottom type continuous annealing furnace to carry out full-continuous annealing production on the drywall nail steel semi-finished steel wire, wherein the inlet end and the outlet end of the roller bottom type continuous annealing furnace are both provided with a vacuum air lock chamber, and RX and nitrogen are used as protective gases of the drywall nail steel wire, so that the decarburization quality of the surface of a product can be ensured, and the technological ideas of high heating temperature and fast roller speed can be adopted. The invention reasonably designs the roller speed according to the length parameters of each process section of the roller-hearth continuous annealing furnace, balances the heating temperature and the heating time, and balances the slow cooling temperature and the slow cooling time, thereby not only meeting the product quality requirement, but also improving the yield and reducing the comprehensive production cost.)

1. An annealing process of a drywall nail steel semi-finished steel wire is characterized in that: comprises the following steps:

(1) a roller hearth type continuous annealing furnace is adopted to divide a furnace zone into 11 zones, wherein the lengths of 1-3 zones are respectively 4 meters, 4.8 meters and 6.3 meters, the lengths of 4-7 zones are respectively 5.2 meters, the length of 8 zone is 3.4 meters, and the lengths of 9-11 zones are respectively 4 meters, 4.8 meters and 6.3 meters;

(2) the 1-3 area of the annealing furnace is a process preparation area, the set temperature of the 4 area is 650 ℃, the set temperature of the 5 area is 680 ℃, the set temperature of the 6 area is 720 ℃, the set temperature of the 7 area is 720 ℃, the set temperature of the 8 area is 680 ℃, the set temperature of the 9 area is 660 ℃, the set temperature of the 10 area is 620 ℃ and the set temperature of the 11 area is 550 ℃;

(3) the vacuum degree of the vacuum chamber before and after the annealing furnace is not more than 0.1 mbar;

(4) 1080 oxygen potential in the annealing furnace is set, the protective atmosphere is RX gas and nitrogen, the dosage of the RX gas is 25m3/h, and the composition of the RX gas is CO: 19 to 21 percent; h₂：38-42％；CO₂: 0.25-0.45% and the balance of N₂(ii) a The nitrogen dosage is 60m³H, the purity is more than or equal to 99.995 percent;

(5) and loading the steel wire coil by adopting a chassis bracket to sequentially pass through each process area in the annealing furnace, wherein the roller speed is 1.85 m/h, and finishing annealing.

2. The process of annealing a drywall nail steel semi-finished steel wire as set forth in claim 1, wherein: the semi-finished steel wire is not more than 65HRB after annealing hardness.

3. The process of annealing a drywall nail steel semi-finished steel wire as set forth in claim 2, wherein: the fluctuation range of the annealing hardness of the semi-finished steel wires in the same batch is within 5 HRB.

4. The process of annealing a drywall nail steel semi-finished steel wire as set forth in claim 1, wherein: the semi-decarburized layer on the surface of the steel wire after annealing is less than or equal to 0.10mm, and no full decarburized layer exists.

Technical Field

The invention relates to the technical field of annealing processes, in particular to an annealing process of a semi-finished steel wire for drywall nail steel.

Background

Drywall nail series is one of the most important major groups of overall fastener production lines, primarily for the installation of various gypsum board, lightweight partition and drop ceiling series. The steel grade of the steel for the dry wall nail is SWRCH22A, a hot rolled wire rod with the production process flow of phi 6.5mm is shelled on a straight wire drawing machine, continuously drawn into a semi-finished steel wire with the phi 2.3mm to 5.25mm, and wound, annealing treatment is carried out to reduce the hardness of the steel wire due to processing hardening, and the annealing treatment is carried out to ensure that the hardness, decarburization and spheroidization grade of the steel wire meet corresponding technical requirements; and (4) carrying out acid pickling and drawing (the drawing amount is not more than 10%) after the annealing is finished, and delivering to a fastener factory to produce the drywall nail.

At present, semi-finished steel wires of the drywall nail steel SWRCH22A are generally annealed by a well annealing furnace, but the well annealing furnace has less furnace loading amount and low yield; during production, nitrogen is used as protective gas, and the depth of the surface decarburized layer is higher; the hardness fluctuation is large, so the well annealing furnace is used for annealing the semi-finished steel wire of the drywall nail steel SWRCH22A, and the comprehensive production cost is high.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: in order to overcome the defects in the prior art, the invention provides the annealing process of the drywall nail steel semi-finished steel wire with low product decarburization, high heating temperature, long heat preservation section and low product hardness, and the production cost is reduced.

The technical scheme adopted by the invention for solving the technical problems is as follows: an annealing process of a drywall nail steel semi-finished steel wire comprises the following steps:

(1) a roller hearth type continuous annealing furnace is adopted to divide a furnace zone into 11 zones, wherein the lengths of 1-3 zones are respectively 4 meters, 4.8 meters and 6.3 meters, the lengths of 4-7 zones are respectively 5.2 meters, the length of 8 zone is 3.4 meters, and the lengths of 9-11 zones are respectively 4 meters, 4.8 meters and 6.3 meters;

(2) the 1-3 area of the annealing furnace is a process preparation area, the set temperature of the 4 area is 650 ℃, the set temperature of the 5 area is 680 ℃, the set temperature of the 6 area is 720 ℃, the set temperature of the 7 area is 720 ℃, the set temperature of the 8 area is 680 ℃, the set temperature of the 9 area is 660 ℃, the set temperature of the 10 area is 620 ℃ and the set temperature of the 11 area is 550 ℃;

(3) the vacuum degree of the vacuum chamber before and after the annealing furnace is not more than 0.1 mbar;

(4) 1080 oxygen potential in the annealing furnace is set, the protective atmosphere is RX gas and nitrogen, the dosage of the RX gas is 25m3/h, and the composition of the RX gas is CO: 19 to 21 percent; h₂：38-42％；CO₂: 0.25-0.45% and the balance of N₂(ii) a The nitrogen dosage is 60m³H, the purity is more than or equal to 99.995 percent;

(5) and loading the steel wire coil by adopting a chassis bracket to sequentially pass through each process area in the annealing furnace, wherein the roller speed is 1.85 m/h, and finishing annealing.

The annealed hardness of the semi-finished steel wire is not more than 65HRB, and the fluctuation range of the annealed hardness of the semi-finished steel wire in the same batch is within 5 HRB; the semi-decarburized layer on the surface of the steel wire after annealing is less than or equal to 0.10mm, and no full decarburized layer exists.

The invention has the beneficial effects that: the invention uses the roller-hearth continuous annealing furnace to carry out annealing production on the dry wall nail steel semi-finished product steel wire, realizes full continuous production, and has high roller speed, high yield and low cost; the inlet end and the outlet end are both provided with vacuum air lock chambers, RX and nitrogen are used as protective gas of semi-finished steel wires, and the decarburization of the product is low; high heating temperature, long heat preservation section and low product hardness.

Detailed Description

The technical solution of the present invention is further illustrated by the following specific examples.

Example 1, a semi-finished steel wire phi 2.78mm drawn from SWRCH22A of phi 6.5mm is illustrated.

An annealing process of a drywall nail steel semi-finished steel wire comprises the following steps:

(1) the steel wire comprises the following components in percentage by weight: c0.19 wt.%, Si 0.03 wt.%, Mn 0.82 wt.%, S0.08 wt.%, P0.13 wt.%, Cr 0.02 wt.%, Ni 0.01 wt.%, Cu 0.02 wt.%, Al 0.042 wt.%, N0.0028 wt.%, balance Fe and impurities;

(2) a roller-hearth continuous annealing furnace is adopted, the furnace zone is divided into 11 zones, the lengths of the 1-3 zones are respectively 4 meters, 4.8 meters and 6.3 meters, the lengths of the 4-7 zones are respectively 5.2 meters, the length of the 8 th zone is 3.4 meters, the lengths of the 9-11 zones are respectively 4 meters, 4.8 meters and 6.3 meters, and the roller speed is 1.85 meters per hour;

(3) the 1-3 zones of the annealing furnace are preparation zones, the set temperature of the 4 zones is 650 ℃, the set temperature of the 5 zones is 680 ℃, the set temperature of the 6 zones is 720 ℃, the set temperature of the 7 zones is 720 ℃, the set temperature of the 8 zones is 680 ℃, the set temperature of the 9 zones is 660 ℃, the set temperature of the 10 zones is 620 ℃ and the set temperature of the 11 zones is 550 ℃;

(4) the vacuum degree of the vacuum chamber before and after the annealing furnace is not more than 0.1 mbar;

(5) oxygen potential 1080 in the annealing furnace, RX gas for protective atmosphere, dosage 25m³The composition of RX gas is CO: 19 to 21 percent; h₂：38-42％；CO₂: 0.35% and the balance N₂(ii) a The nitrogen dosage is 60m³H, the purity is more than or equal to 99.995 percent;

(6) and loading the steel wire coil by adopting a chassis bracket to sequentially pass through each process area in the annealing furnace, wherein the roller speed is 1.85 m/h, and finishing annealing.

And the steel wire comes out from the 11 th area of the roller-hearth continuous annealing furnace, the annealing process is finished, and the steel wire sequentially enters the subsequent pickling process, the fine drawing process and the packaging process and then is put in storage.

Example 2.phi 6.5mm SWRCH22A drawn to phi 3.7mm semi-finished steel wire.

An annealing process of a drywall nail steel semi-finished steel wire comprises the following steps:

(1) the steel wire comprises the following components in percentage by weight: c0.20 wt.%, Si 0.04 wt.%, Mn 0.79 wt.%, S0.09 wt.%, P0.11 wt.%, Cr 0.02 wt.%, Ni 0.01 wt.%, Cu 0.02 wt.%, Al 0.039 wt.%, N0.0025 wt.%, the balance being Fe and impurities;

(2) a roller hearth type continuous annealing furnace is adopted, the furnace zone is divided into 11 zones, the lengths of the 1-3 zones are respectively 4 meters, 4.8 meters and 6.3 meters, the lengths of the 4-7 zones are respectively 5.2 meters, the length of the 8 th zone is 3.4 meters, the lengths of the 9-11 zones are respectively 4 meters, 4.8 meters and 6.3 meters, and the roller speed is 1.85 meters per hour;

(3) the 1-3 zones of the annealing furnace are preparation zones, the set temperature of the 4 zones is 650 ℃, the set temperature of the 5 zones is 680 ℃, the set temperature of the 6 zones is 720 ℃, the set temperature of the 7 zones is 720 ℃, the set temperature of the 8 zones is 680 ℃, the set temperature of the 9 zones is 660 ℃, the set temperature of the 10 zones is 620 ℃ and the set temperature of the 11 zones is 550 ℃;

(4) the vacuum degree of the vacuum chamber before and after the annealing furnace is not more than 0.1 mbar;

(5) oxygen potential 1080 in the annealing furnace, RX gas for protective atmosphere, dosage 25m³The composition of RX gas is CO: 19 to 21 percent; h₂：38-42％；CO₂: 0.35% and the balance N₂(ii) a The nitrogen dosage is 60m³H, the purity is more than or equal to 99.995 percent;

(6) and loading the steel wire coil by adopting a chassis bracket to sequentially pass through each process area in the annealing furnace, wherein the roller speed is 1.85 m/h, and finishing annealing.

And the steel wire comes out from the 11 th area of the roller-hearth continuous annealing furnace, the annealing process is finished, and the steel wire sequentially enters the subsequent pickling process, the fine drawing process and the packaging process and then is put in storage.

Example 3.phi 6.5mm SWRCH22A drawn to phi 4.6mm semi-finished steel wire.

An annealing process of a drywall nail steel semi-finished steel wire comprises the following steps:

(1) the steel wire comprises the following components in percentage by weight: c0.19 wt.%, Si 0.04 wt.%, Mn 0.83 wt.%, S0.09 wt.%, P0.12 wt.%, Cr 0.02 wt.%, Ni 0.01 wt.%, Cu 0.02 wt.%, Al 0.04 wt.%, N0.0030 wt.%, the balance being Fe and impurities;

(2) a roller hearth type continuous annealing furnace is adopted, the furnace zone is divided into 11 zones, the lengths of the 1-3 zones are respectively 4 meters, 4.8 meters and 6.3 meters, the lengths of the 4-7 zones are respectively 5.2 meters, the length of the 8 th zone is 3.4 meters, the lengths of the 9-11 zones are respectively 4 meters, 4.8 meters and 6.3 meters, and the roller speed is 1.85 meters per hour;

(3) the 1-3 zones of the annealing furnace are preparation zones, the set temperature of the 4 zones is 650 ℃, the set temperature of the 5 zones is 680 ℃, the set temperature of the 6 zones is 720 ℃, the set temperature of the 7 zones is 720 ℃, the set temperature of the 8 zones is 680 ℃, the set temperature of the 9 zones is 660 ℃, the set temperature of the 10 zones is 620 ℃ and the set temperature of the 11 zones is 550 ℃;

(4) the vacuum degree of the vacuum chamber before and after the annealing furnace is not more than 0.1 mbar;

(5) oxygen potential 1080 in the annealing furnace, RX gas for protective atmosphere, dosage 25m³The composition of RX gas is CO: 19 to 21 percent; h₂：38-42％；CO₂: 0.35% and the balance N₂(ii) a The nitrogen dosage is 60m³The purity is more than or equal to 99.995 percent.

(6) And loading the steel wire coil by adopting a chassis bracket to sequentially pass through each process area in the annealing furnace, wherein the roller speed is 1.85 m/h, and finishing annealing.

And the steel wire comes out from the 11 th area of the roller-hearth continuous annealing furnace, the annealing process is finished, and the steel wire sequentially enters the subsequent pickling process, the fine drawing process and the packaging process and then is put in storage.

Comparative example 1

Taking the example of the production of a phi 3.7mm semi-finished steel wire drawn by SWRCH22A with phi 6.5mm and annealed by using a shaft furnace, the annealing process comprises the following steps:

(1) the steel wire comprises the following components in percentage by weight: c0.19 wt.%, Si 0.04 wt.%, Mn 0.83 wt.%, S0.09 wt.%, P0.12 wt.%, Cr 0.02 wt.%, Ni 0.01 wt.%, Cu 0.02 wt.%, Al 0.04 wt.%, N0.0030 wt.%, the balance being Fe and impurities;

(2) annealing by using a phi 3800mm pit furnace, wherein the charging amount is 30 tons, and the annealing process comprises the following steps: heating to 580 ℃, keeping the temperature for 60 minutes, then heating to 660 ℃, keeping the temperature for 60 minutes, then heating to 700 ℃, keeping the temperature for 300 minutes, and then starting to cool; the annealing period is 22 hours;

(3) the protective gas used for annealing is nitrogen, and the dosage is 60m³The purity is more than or equal to 99.995 percent.

The quality test data of the above examples 1, 2 and 3 and comparative example 1 are shown in Table 1.

TABLE 1

As can be seen from Table 1, the quality of the semi-finished steel wire produced by annealing in the roller hearth type continuous annealing furnace is significantly superior to that produced by annealing in the pit furnace.

In the embodiment 1, the embodiment 2 and the embodiment 3 of the invention, a roller-hearth continuous annealing furnace is adopted, the roller speed is 1.85 m/h, and one chassis bracket enters and exits every 110 minutes. Each chassis carrier is loaded with 8 wire coils of 850mm diameter and 2.2 tonnes by weight, and the daily output is calculated as 2.2 tonnes/column x 8 x 24 x 60/110-230.4 tonnes; the annealing period of the pit furnace is 22 hours, and the annealing period is 24 hours with auxiliary time, namely only 30 tons of products can be produced each day.

The production costs of examples 1, 2 and 3 according to the invention compared with comparative example 1 are shown in table 2 below:

TABLE 2

In light of the foregoing description of the preferred embodiment of the present invention, many modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.