In the production of cold-drawn seamless steel pipes, the tube billet cost accounts for 80-85% of the production cost. Reducing metal consumption, especially reducing the tangible consumption of cutting heads and tails during steel pipe production and the intangible consumption of pickling after annealing, can significantly reduce production costs and improve the economic benefits of enterprises. Production practice and scientific research show that tube billets that are too long or too short not only consume a lot of metal but also affect the number of intermediate cutting times of steel pipes and the changes in the intermediate cold wall processes, thereby affecting the number of annealing and pickling lubrication. For a long time, the tube billet cutting length has been determined by experience, which is difficult to be scientific and standardized.
1) As the length of the tube billet increases, the production cost decreases;
2) When other conditions are the same, the number of hammering (including head modification), cutting, annealing, and pickling increases, and the production cost increases;
3) The order of hammering (including head modification), cutting, annealing, and pickling moves to the front pass, and the production cost increases;
4) When producing 20×3mm 20 steel pipes, the tube billet length varies in the range of 590~1250mm, and the production cost of the tube billet cutting length of about 850mm is the lowest. The difference between the highest and lowest costs is 584.11 yuan/ton.
When other conditions are the same, the longer the tube billet length, the longer the length of the product pass steel pipe, the fewer feeds per ton of product steel pipe, the fewer heads and tails are cut, and the metal recovery rate is increased, so the production cost is reduced.
The number of head modifications, hammering, and cutting is reduced, the tangible consumption of head and tail cutting is reduced, and the production cost is reduced; the number of pickling, lubrication, and annealing is reduced, the gas consumption, acid consumption, and lubricant consumption are reduced, and the production cost is also reduced.
The order of head modification, hammering, and cutting is moved forward, the unit weight of the pipe head is increased, the tangible consumption of metal is increased, and the production cost is increased. Since the annealing time of large-diameter thick-walled pipes is longer than that of small-diameter thin pipes, and the iron oxide scale is thicker, the order of pickling, lubrication, and annealing is moved forward, which not only increases the gas consumption per ton of steel pipe but also increases the intangible consumption during pickling, both of which increase its production cost.
Post time: Oct-31-2024