Through the stainless steel annealing pickling line upgrade, successfully overcome the aging of the production line and the problems caused by the design of the old.
A) modernization of the shop, making any possible improvements, minimizing changes in line layout and avoiding major changes to the operator interface, the standard process book and the process specifications;
B) replacement of obsolete equipment to improve strip quality;
C) Minimize the impact on the environment;
D) The minimum amount of civil works.
In accordance with these requirements, civil engineering, equipment installation and commissioning time and final commissioning work can be minimized to achieve the same level of productivity and quality as before, followed by equipment commissioning to improve product quality and a small number of future Upgrading, thereby improving productivity.
The main technical parameters of the production line are as follows: The hot-rolled and cold-rolled stainless steel strips (AISI 200, 300, 400 series stainless steel and titanium belt) can be processed in the production line. The thickness of the hot rolled strip is 2mm ~ 7mm, the cold band thickness is 1.3mm ~ 5mm, ~ 1500mm. Production line design maximum yield of 50t / h cold-rolled strip.
In the entrance section, the most important work is to revitalize the loop sleeve. In fact, the existing loops (20m deep) must be replaced with a new horizontal looper. The new four-wire looped trolley is moved on a sloping plane so that the curved head and tail are modified when the belt is being worn.
When tensioning the oiled cold strip, all pinch rolls, guides, and loop lengths in the entry section are recalculated.
Heat treatment section
The annealing furnace section was completely modified, the installation of a new preheating room, recycling waste heat from the flue gas, preheating into the annealing furnace with the coil. This section is particularly advantageous for the production of cold-rolled strip because the rolling oil remaining on the surface of the strip can be burned at a lower temperature.
The complete cover of the annealing furnace is updated to reduce time-consuming on-site structural restoration. In addition, the replacement of a new annealing furnace measuring instruments, valves and control systems. The inlet and outlet front walls are closed with special sealing means to minimize the ingress of outside air into the furnace.
The existing old cooling section is fully renewed and an innovative "multi-media" cooling section is used to produce high-quality strip (flatness) in the absence of space for the mechanical descaling-straightening section. The "multi-media" cooling section consists mainly of air + mist sections, fog sections and water jet sections. The temperature gradient in the first section is specially designed to prevent carbide precipitation (especially for hot-rolled strip) while ensuring a temperature gradient Small and uniform, so as not to affect the strip flatness. Based on this consideration, the cooling section uses a special ramp to adjust the strip width direction cooling effect.
The exhaust gas filtration system in the cooling section is specially designed so that the exhaust gas is drawn into the "multi-media tank" where it is separated into the water sedimentation pits by centrifugation. The air is then passed through a special water droplet separator, Through the exhaust fan row chimney. A new guide and tension control section is installed at the exit side of the cooling section, which consists of a single roll guide, tension roller and looper tensioner. The special roll crown and steering angle were studied, and the cooling section, annealing furnace geometry and thermal cycle were calibrated. The crown and flatness of the strip were improved by cooling section control.
Surface treatment section
High-power turbine shot blasting machine from the original annealing pickling line disassemble and re-use to adapt to the new line layout.
The pickling section was refurbished and significantly modified using an environmentally friendly pickling solution developed by ThyssenKrupp, which has low operating and post-treatment costs. In the pickling section, the first slot using sulfuric acid to remove the surface oxide scale, No. 2 slot acid cleaning, slot 1, slot 2 and slot 3 are using the traditional submerged roller design, the use of low-pollution acid, which can Avoid the use of nitric acid, eliminating the waste acid in the nitrate and flue gas nitrogen oxides exist.
Another innovative device is the "steam box," which removes dust from the strip that remains on the surface after the spray finish and pre-heats the strip to increase the efficiency of the pickling tank.
All recycle equipment including pickling tank, piping and support equipment, heat exchanger arrangement, equipment, etc. are re-designed to improve the operation of the section and security. Installation of new acid storage tanks and buffer tanks, processing and storage of the temporary excretion of acid during the maintenance of the production line and the need to pump water to the wastewater treatment plant. 1, and the final cleaning equipment, rinse No. 3, rinse and dry sections are replaced with new equipment. Slot 1 has been adapted to accommodate the existing guide-squeeze roll equipment. The tank 3 was thoroughly reformed to improve the effect of acid turbulence and temperature rise, and set aside the future installation of extended immersion high turbulence pickling tank space. In addition, the replacement of the new two-stage acid gas emissions system to meet local stringent environmental emission requirements.
2) Retain the original mode of operation; 3) Retrofit the automation system, using better control, human control, and automation. The automation and automation systems are developed according to the objectives set by the customer: 1) Retain the equipment disassembled from the Turin plant as much as possible; Machine interface, diagnosis, interface and 2-level automation;
In-depth investigation of the site, check the existing documents, select the equipment to be retained and check the operating procedures, according to these analyzes, a complete and careful dismantling and removal of equipment, renovation project.
Due to changes in market conditions during the implementation of the project, engineering test time had to be significantly shortened, due to technical staff and the tireless efforts of the standardization process, the final construction of the production line test time shortened by 4 weeks.
Industrial technology, stainless steel groove tube for continuous hot-dip galvanizing continuous online annealing. Annealing process is the key to the production of hot-dip galvanized steel products such as duplex steel, which has a great influence on the enrichment of Mn, Si and other elements on the steel plate surface, which will affect the platingability and surface quality of high strength steel.
In general, the Guangdong stainless steel groove tube manufacturers point of view, the stainless steel groove tube annealing process usually includes preheating, heating, soaking and cooling process. Preheating the strip with the heated exhaust gas not only saves fuel, but also avoids the deformation of the strip due to the rapid heating rate of the strip, which is very advantageous to the thin plate shape.
Some units of the cooling process using the first cooling after the fast cooling of the sub-cooling, both to avoid excessive cooling rate caused by poor shape, but also to meet the dual-phase steel and other high-strength steel cooling rate requirements. Annealing furnace roll design, the furnace annealing atmosphere and dew point control, furnace tension control and annealing furnace roll surface coating is also the focus of hot-dip galvanizing annealing process, thin strip shape and high strength steel plate stability Sex also needs to be studied in depth.
For the stainless steel groove tube cleaning process analysis as follows:
Stainless steel grooved pipe cleaning usually includes alkaline scrubbing and electrolytic degreasing. It can remove impurities such as iron scrap and oil on the surface of cold rolled steel sheet. It is very important to produce galvanized products with high surface quality and high coating adhesion. For the production of stainless steel groove tube hot galvanized unit cleaning section, including alkaline lye, alkaline scrubbing, electrolytic cleaning, hot water scrubbing, hot water rinse, cleaning and drying, washing and drying can strip the residual oil and residues The total amount of carbon is controlled below 20mg / m2, which meets the requirement of cleaning quality of hot-dip galvanized automobile outer plate. It adopts the grinding wheel with SiO2 abrasive grains, and grinds the surface of strip to improve the adhesion of GA coating.
Zhangjiagang City Ka Wah Furnace Industry Co., Ltd. is a collection of scientific research and development, manufacturing and sales services as one of the high-tech enterprises in Jiangsu Province. Our products are mainly used in metallurgy cold rolling industry, seamless steel pipe industry, high pressure cylinder industry, automobile engine industry, casting and forging industry, nonferrous metal heat treatment and other industries. The company's main products are: strong cycle of high hydrogen, hydrogen bell-type strong cycle of bright annealing furnace, continuous annealing furnace, metal heat treatment industrial furnace, skim line, color plate line, hot dip galvanizing line, tin line, (Copper) tube heat treatment production line, step-by-step high-pressure gas cylinder heat treatment production line, roller-type high-pressure gas cylinder heat treatment furnace, high-pressure gas cylinder heat treatment furnace, heat treatment furnace, Horizontal multi-row curing furnace and large-scale desktop heat treatment furnace. There are natural gas, liquefied gas, hot gas, cold gas, electric heating five series of low-power furnace, respectively, nitrogen, ammonia decomposition and hydrogen protection atmosphere. Production equipment supporting the main metallurgical cold-rolled, non-ferrous metal processing, building materials components, standard parts and other industries, some products exported overseas, large-scale furnace also supporting foreign well-known enterprises. Ka Wah Furnace has accumulated years of production history and rich experience in the design and manufacture, strong technical force, with a full range of large-scale processing equipment and advanced detection technology and equipment, is the industry with large-scale professional heat treatment equipment manufacturer, Is the ISO9000 quality system and 14000 environmental quality system certification enterprises.
Ka Wah Furnace in the output of sophisticated equipment at the same time, with great concentration to create service brands, in good faith and professional service concept, the maximum to meet customer needs. The company aims to energy efficient, clean environmental protection heat treatment equipment, and guide the industry trend, improve the level of industrial technology.