At the beginning of the new year, the project of two drum blender-reclaimer signed by North Heavy Industry Co., Ltd. and Shandong Iron and Steel Group Yongfeng Lingang Co., Ltd. has entered a critical stage of production. This is the second time that NHI produced the same type of products after more than 20 years. NHI has further consolidated its leading position in the industry in the market of bulk loading and unloading and metallurgical equipment,

Butterfly Regeneration Obtained User Approval

NHI has a long history, which is merged from the former Shenyang Heavy Machinery Factory and Shenyang Mining Machinery Factory. Shenyang Mining Machinery Factory was founded in 1921, it has been a hundred years. For a period of time, restricted by the rigid system and mechanism and affected by the downward economic situation at home and abroad, NHI has been hovering in the trough period. After the implementation of the mixed ownership reform, Fangda Group, as a strategic investor, brought the modern enterprise system and mechanism, management mode, abundant capital, support of market resources and brand new enterprise culture to NHI, rapidly forming a market-oriented governance structure and operation mechanism. With the strong support of Fangda Group, NHI rapidly integrates its own advantages in technical resources, adjusts the product structure, implements product upgrades, comprehensively enhances the core competitiveness in the segmented market, and stimulates the survival and development ability of the enterprise in the market.

Under this background, NHI takes the initiative to seek the market. After learning that the first-phase project of Linyi Lingang Advanced and Excellent Special Steel Industry Base was tendered, NHI actively visited the users and invited Yongfeng Lingang Co., Ltd. of Shandong Iron and Steel Group to send special personnel to NHI for investigation to evaluate the supply capacity and manufacturing level of the enterprise. In this bidding project, the drum mixing reclaiming machine is the manufacturing difficulty. NHI has been recognized by users for its best cost performance scheme. After several rounds of in-depth understanding and comparison, NHI won the customer's approval with the best cost performance scheme, beating domestic and foreign competitors to win the contract.

Carefully Planning Break Technological Barriers

The production of drum blender-reclaimer is about 40 meters in length, the total length of cylinder diameter is 4.35 meters, which is a three-stage cylinder flange welding connection structure, the outer shell plate thickness is 16 mm, the thickness of the inner tube is 6mm, due to the difficulty of bending type, high requirement of flaw detection and tight construction period, how to deliver on time on the premise of ensuring product quality has become the biggest problem of this project.

The cylinder length of 40 meters and the wall thickness of the inner cylinder of 6mm are destined to be extremely difficult to control the outer dimension of the cylinder and even more difficult to guarantee the coaxiality. In order to solve the manufacturing technology of the key difficulties, NHI organizes and holds special meeting with technology professionals, first-line operation backbone to discuss the manufacturing difficulties and the related problems that may appear in the process. A complete manufacturing process plan was developed by combining with the actual situation of welding.  

In order to shorten the production cycle to the maximum extent under the premise of ensuring the quality, the technical backbone has optimized the assembly and vertical welding process, the driving end and its processing are added, as well as the annular support in the cylinder section. The center of the end face of the cylinder is determined by machining knife inspection method and the center hole is punched in the end face. Laser measurement method is used to ensure the coaxiality of the driving end and the driven end of the cylinder. In the welding process, the welding heat input and welding deformation are strictly controlled by multi-pass welding and small specification of welding parameters. Through the above optimization, the reliability of the welding process of the product has been greatly improved, and the production efficiency has been improved while ensuring the quality of the product. The manufacturing cycle of nearly 10 days has been shortened, which provides strong support for the smooth completion of the project.

Strictly Uphold Quality Red Line

In the actual production process, welding personnel strictly control the production process of each procedure. The bending requirements of the cylinder body are guaranteed by increasing the bending type of the curved plate and the split bending type. The inner and outer shell is welded together according to the specified size through the combination of vertical and horizontal joints of the cylinder body. By reserving the welding expansion allowance of the length of the cylinder, the working difference of the length of the cylinder can be effectively guaranteed.

At the same time, the person in charge of production and quality shall track the whole process of the project, make daily plans and conduct daily supervision through process optimization, schedule all available resources inside and outside the plant, arrange 24-hour operation of relevant equipment, and ensure the smooth completion of the project schedule. At present, all the employees involved in the project are working hard for days, which are expected to shorten the production cycle by nearly 25 days compared with the same type of products. The striving spirit of NHI has been recognized by the supervision users.