Stone steel casting blank cutting technology transformation

The quality of the cutting is not good, and there are often problems such as large chamfering, slanting, incision, and slag loading. In severe cases, production quality accidents such as difficulty in rolling the top billet and billet are severely affected, which seriously affects the physical quality of the billet. At the same time, it has increased metal loss and labor intensity.

Table 1 Corrosion comparison of Shigang continuous casting machine. Technical transformation 3.1 Propane gas cutting reaction principle Shigang slab cutting technology transformation Gaochun (Hebei Iron and Steel Group Shigang Steelmaking Plant, Shijiazhuang 050031, Hebei Province) is improper, easy to cause casting billet cutting Metal splashes, uneven sections, and large cuts. The Shigang Steel Plant reduced and cut the slab of the slab by reducing and cutting the cutting throat diameter of the flame cutting system from 2.6mm to 1.40 mm, the valve box regulator and the solenoid valve, and the media parameters of the cutting machine. And the burning consumption has achieved remarkable results.

Engineering major, now working at Hebei Steel Group's Shigang Steelmaking Plant, E-mail: propaneization 3) The molecular weight is 44.06, and the density at 0 ft is 2.014 g/L, which is heavier than air. Generally deposited in pits and trenches on the ground, it will burn when exposed to fire. When the volume ratio in the air is 2.3% ~ 9.5%, the Mars will explode. The combustion heat value is 93424k/m3, and the flame cutting of the propane gas combustion temperature 2 is the reaction process of metal and 2, which is heated to the melting point by using a flame of preheated oxygen and gas mixed combustion, and then opens the high pressure cutting oxygen to reach The cutting zone of the melting point ejects high purity, high pressure 2, which fully oxidizes the metal in the zone and releases a large amount of thermal energy. During the oxidation process, the formed slag is blown off by the high pressure 2 stream; the heat released during the oxidation starts from the preheating flame, and the metal in the cutting direction is continuously heated to the melting point to form a continuous cut until the slab is completely cut. It can be seen that the role of the gas flame during gas cutting is to preheat the slab and cut oxygen to ensure the oxidation reaction temperature of the slab at the cutting point.

3.2 Analysis of the causes of the problem The main reasons for the problem of the quality of the cut slab are as follows: the cutting torch and the cutting throat are not properly selected, and the streamline design is unreasonable.

Cutting oxygen, preheated oxygen and gas pressure are not properly selected, poorly matched or pressure unstable.

The gun position or cutting speed is not set properly.

3.3 Specific implementation methods After detailed calculation, testing and tracking adjustment, the flame cutting gun, cutting nozzle and point valve box are modified to determine and solidify the cutting medium parameters. The main measures are as follows.

The specially designed flame cutting gun and cutting nozzle are selected. Through the test tracking, the cutting throat diameter is improved from the original 2. 4mm under the premise of ensuring the cutting quality, which improves the combustion stability and reduces the slit width of the casting blank.

Modification of the point valve box regulator and solenoid valve, precise control 2, gas flow and pressure.

The media parameters matching the cutting tools after the transformation were found out, and the cutting oxygen, preheating oxygen and gas use pressure were significantly lower than before the transformation.

Implement property management on cutting tools and gas supply, write relevant operation and media parameter settings into operating procedures to ensure the stability of the cutting system.

Strictly control the quality of the combustion medium to ensure 2 purity> technical transformation effect of the transformation of the media parameters: cutting oxygen pressure 0.9 ~ 1.1MPa, preheated oxygen pressure 矣 0. 3MPa, gas pressure before and after the machine technology change, two flow flame cutting A picture of the machine's flame. In the middle, the left side is the flame cutting after the transformation, waiting for the flame condition, and the right side 3, 4, 5 flow is the flame cutting waiting for the flame before the transformation.

It can be seen that whether the dynamic cutting or the static waiting cutting, the modified flame is significantly smaller than the flame before the transformation, which means that the gaseous fuel wasted in the state where the flame cutting machine is not working is significantly reduced. At the same time, it also reduces the amount of C2 emissions during combustion. With 20 bottles of industrial gas as the statistical unit, the gas consumption is extended from 56h before the improvement to 68h. It can be seen that the slab is cut with the normal cutting and pulling speed of the 45 steel slab, using 2.5mm, 3mm feeler gauge. For the measurement, the 150mmX150mm casting blank can be kept between 2.5~3mm. It can be seen that the slab is cut with normal cutting and stable drawing speed, and measured with a 5mm feeler gauge. The width of the kerf can be kept at 5mm, while the width of the original kerf is 10.5mm. Compared with the width of the cut, the width of the slit after the transformation is even and flat, no chamfering occurs, and the cutting is obviously reduced.

After the transformation of the benefit calculation, the width of the cutting blank of the casting blank is obviously reduced, in which the billet (0 machine, 2 machine) is cut by 3mm, and the average is reduced by 3mm; the billet (3 machine, electric furnace bloom) is cut by 5mm, and the average is reduced. 4mm. Conclusion Through the comprehensive technical transformation of the continuous casting flame cutting system, it has achieved remarkable results in reducing the slab kerf and combustion consumption. The cutting width of the billet (0 machine, 2 machine) is reduced from the average 6mm before the improvement to 矣3mm, and the slit of the bloom (3 machine, electric furnace bloom) is reduced from the average 9mm before the improvement to 矣5mm; The cutting surface of the casting blank is flat, the cutting of the tumor is small, and there is no cutting and impervious phenomenon, which reduces the labor intensity of the employees; the gas consumption is reduced to 85% before the transformation, and the energy saving and consumption reduction effect is good. The stability and safety of the billet cutting system have been significantly improved, and the economic benefits are remarkable.

(Continued from page 53) Treatment measures When the hydraulic system is lowered, it sometimes shakes. The reason is that the overflow main pipe of the safety valve block of the lift cylinder is connected to the overflow pipe of the proportional valve of the valve table, resulting in poor overflow of the oil cylinder.

Treatment method: Connect the overflow pipe to the main overflow pipe according to the system diagram.

The slab runaway amount far exceeds the normal runoff amount, and it is suspected that there is a large angle between the horizontal frame centerline and the furnace centerline.

Treatment method: Adjust the four guide rollers of the horizontal frame when the furnace is stopped, so that the center line of the horizontal frame is offset toward the discharge furnace door.

After the effect of improving the hydraulic system overflow pipe, the hydraulic system works stably, and the lifting cylinder no longer shakes when working; after adjusting the horizontal frame guide roller, the slab offset in the furnace is significantly reduced and the secondary adjustment is achieved.

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