The company possesses a comprehensive set of process flows, including smelting, electroslag remelting, forging, rolling, shearing, machining, heat treatment, and surface treatment. It can further utilize returned materials and scraps. Zhejiang Zhongjian will gradually phase out its own smelting capacity in the future, procure slabs from large state-owned enterprises for backend processing, and extend the industrial chain towards deep-end processed products.
1. Smelting
Our high-quality tools and molds undergo initial melting and alloy adjustment, as well as slag removal, through induction furnaces. The relatively small size of our induction furnaces ensures greater flexibility in our process, allowing Zhongjian to smelt small batches, multiple varieties, and customized special steel grades for our customers.
In addition, the advantage of induction furnaces lies in minimizing the loss of alloy elements during the smelting process of tools and molds, resulting in a high alloy yield; precise and stable control of chemical composition; and high utilization rate of return materials, effectively reducing costs.
During the smelting process, we analyze the chemical composition of the sample multiple times using a spectrometer, and make fine adjustments in subsequent steps to ensure accurate alloy composition.
2. LF+VD secondary refining
Through our subsequent external furnace technology processing, we can elevate the quality of our tool and mold materials to a higher level.
We adopt the LF+VD secondary refining process to effectively remove gases such as N and O from the molten steel and enhance its purity, thereby meeting the increasingly complex market demands and domestic standards for high-quality tool and die steel.
3. ESR electroslag remelting
High-quality electroslag ingots can be produced through our atmosphere-protected electroslag remelting equipment, which improves the crystallization structure of the ingots;
Reduce non-metallic impurities and inclusions in steel;
Control the atmosphere inside the furnace to prevent an increase in the content of H, N, and O in steel. Meet customer requirements for high purity materials.
4. Forging/rolling and cogging
Through forging/rolling and cogging processes, the electroslag ingots are thermally processed and deformed into semi-finished slabs suitable for rolling; or they can be made into forging billets of different specifications as finished products of flat steel. With our 8T air hammer or 1700 rolling mill, the ledeburite and banded carbides in high-speed steel ingots can be fully crushed to obtain a fine and dispersed microstructure. The carefully controlled annealing process ensures the optimal forging billet microstructure and processability.
5. Rolling
The plates with customizable dimensions can be produced on Zhongjian's unique 1400-1250 hot rolling production line and cold rolling workshop, with special attention paid to customer requirements. To ensure high quality, all plates are produced using cross-rolling technology. The plates in delivery status have undergone our leveling process, vacuum annealing process, surface treatment process, etc. Ultrasonic equipment is used to inspect the thickness tolerance of the plates, and surface defects are inspected on every plate to ensure the quality and supply stability of the outgoing plates.
6. Machining
Through subsequent machining processes such as straightening and finishing, laser cutting, stamping and forming, grinding, milling, and CNC machining center.
We can obtain deep-processed derivatives of plates and flat steel, such as circular saw blades, precision plates, planer knives, turning tools, etc. At the same time, we can meet customers' customized needs and customize finished cutting tools according to the requirements of drawings.
7. Heat treatment
In the Zhongjian A area, we possess a standalone heat treatment workshop dedicated to the pre-hardening process of deeply processed products. Through vacuum quenching and tempering, we achieve the red hardness, hardness, strength, and wear resistance of high-speed steel materials.
8. Quality inspection/warehousing
We possess independent warehouses for semi-finished and finished products, utilizing a modern steel WMS (Warehouse Management System) for inventory management.
Ensure that each batch of products dispatched can be traced for quality after-sales service.