Effect of heat treatment on the strong performance of the steel is much larger than the thermal effect on the mechanical properties at room temperature, and enduring strength is the main basis for the design of the boiler, so only take reasonable heat treatment process to obtain excellent organization, in order to ensure long-lasting strength and high temperature, stable performance under high pressure conditions of use.
For the production of the soaking zone heating temperature reaches the desired temperature in order to ensure that the steel requirements, we must rely on the heating section to adjust the temperature and speed furnace roller running speed to achieve, so the temperature control is difficult to ensure the accuracy of each segment, uniformity, stability, to create the conditions for the formation of widmanstatten. Also under serious shortage tube left in the middle widmanstatten inadequate annealing conditions, by normalizing the finished product a short time is difficult to completely eliminate.
After the cold-drawn steel matrix structure for fine crushing of ferrite grains, internal stress is large and easy to crack, and finished in the middle of annealing (or normalized) process, if the annealing (or normalized) time is too short, too late grain recovery grew, the formation of small ferrite grain structure. When the grain of this fine organization of more than 10, will make a substantial increase in the strength of steel at the same time, the plastic lower elongation decreased, and even lead to the yield point is not obvious. Therefore, the heat treatment process, as far as possible while avoiding widmanstatten generated, should ensure the normal tissue and the mechanical properties. The key is to ensure that the finished normalizing normalizing temperature requirements of the standard, enabling organizations to fully recovery and recrystallization avoid widmanstatten.
Due to the high pressure seamless steel quality control technology in all processes detection and non-destructive testing, stress determination, there would be new development. Foundry workers under conditions of high pressure seamless electronics and progressive means of testing, it will crystallize solidification of metal and sand compaction theory more in-depth exploration, to study effective way to improve the performance and internal quality castings. Robotics and computer in casting production and management in the field of application, it will become increasingly widespread. Casting will generate dust, harmful gases and noise pollution on the environment, compared to other mechanical manufacturing processes to more serious measures are needed to control it. High pressure seamless steel casting product development trend is to require casting a better overall performance, better accuracy, less headroom and clean surface.
High pressure seamless steel energy requirements and social restoration of the natural environment are increasingly vocal. To meet these requirements, a new high-pressure seamless steel pipe will be developed, smelting new technology and new equipment will appear accordingly. Automatic casting production mechanization has been improving, while the more flexible production development, to expand the volume and variety of production flexibility.
Saving energy and raw materials will be given priority in the development of new technologies, to produce less or no contamination of new technology and new equipment will first be taken seriously. Machinery and equipment for special casting and equipment used in many transportation and material handling. Casting high pressure seamless steel pipe production and other processes have different characteristics, mainly wide adaptability, needed materials and equipment and more, pollute the environment.
Optimum efficiency control of high frequency welded pipe in welding process
In most cases, optimized welding process, power loss can be reduced 50% and can improve the welding quality, reduce downtime, increase production.
Stress on the trench corrosion of high-frequency straight seam resistance welding pipe
Trench etching is generally believed that acute heat in the welding process, the results of local tissue metal and chemical change caused by quenching.
Technology of straight seam high frequency resistance welded steel pipe
Factors that affect the raw material for the steel pipe welding quality affect the quality of raw materials are mainly steel mechanical properties unstable surface defects and strip geometry deviation big three aspects, therefore, we should focus on these three aspects of control.
