High accuracy weighing of raw materials with belt scales improves steel company’s bottom line.

XinYu Steel is a large steel mill located in XinYu City, China. In operation for more than 50 years, the company is highly focused on innovation and the application of new products. XinYu produces and sells iron and steel products including plates, wires, rebars, tubes, and strips. XinYu markets its products in China, United States, South Korea, Japan, Europe, and Southeast Asia.

During steel production, iron is melted and reprocessed to remove any other carbon in excess of that required as an alloying agent. Other alloying elements can include tungsten, manganese, vanadium, and chromium. Steel is then cast into ingots or slabs to form a variety of products, including sheet metal, plates, bars, wire, and rails.

Increasing efficiency by focusing on the measurement of energy and raw material is a major goal of XinYu. Improving cost accounting processes assists with overall production efficiency. In the steel production system, these processes are mostly based on the measurement of energy and the accounting of raw materials. Precise measurement of raw ingredients is therefore critical to a company’s bottom line.

XinYu processes raw materials for steel production such as coal, ore, and coke (Photo: Siemens AG)

For several years, XinYu experienced problems caused by inaccurate measurement of raw material in the company’s mines, material plants, and other production plants. XinYu attempted to solve the problem by installing electronic belt scales. Unfortunately, the belt scales did not fix the inaccurate measurement and drifted accuracy, so the problem remained. According to steel industry measurement standards, belt scale accuracy of ±0.5% is the standard for internal settlement (processing). The belt scale accuracy of ±0.25% is used as the standard for custody transfer among enterprises. Due to the continuing challenges with their existing belt scales, XinYu required a belt scale with higher accuracy in line with industry standards. For XinYu, belt scales that are consistently reliable for all sites are a must.

A solution for weighing accuracy

With these application requirements in mind during this period of technical reform, XinYu compared various belt scales from a number of different manufacturers. Siemens high-accuracy MSI/MMI series of belt scales made the best impression.

XinYu adopted a suite of Siemens MMI high-accuracy belt scales as their preferred product. This suite included: MMI belt scales, BW500 integrators, and WS300 shaft mounted speed sensors. The MMI frame is composed of two or more MSI scales, which means that it is equipped with four or more load cells. Siemens MSI belt scale series with its compact design, high flow capacity, and high-accuracy uses a single idler directly loaded to the weighing scale frame. This type of frame has no moving or rotating parts, levers, or counterbalances, so it offers long-term stability, high accuracy, and ease of installation and maintenance. Siemens MMI multi-idler belt scale is a high-accuracy belt scale. The accuracy specification of Siemens MMI belt scale features a measuring range of 20 to 100% at ±0.25% accuracy, which fits well with steel industry guidelines.

XinYu started with a trial on the fine ore powder section between the QiuTuan Branch of XinYu Steel and the LiangShan Iron Mine. This is where the custody transfer takes place. Originally, the fine ore powder of LiangShan Iron Mine was transported to QiuTuan Branch directly by the conveyor belt with a domestic electronic belt scale. However, neither party accepted the measurement data, leading to disputes. After completing the calibration and adjusting the integrator’s parameters, Siemens MMI belt scale consistently measures accurately.

Greatly improved measurement and management

The trial of Siemens MSI/MMI series belt scales in the fine ore powder section was very successful and won the approval of the leaders of the QiuTuan branch and LiangShan Iron Mine. Several calibrations conducted during this period all met the accuracy requirements of custody transfer. After this initial trial period, XinYu has adopted a number of MSI/MMI series belt scales in many important measurement processes, such as fine ore powder, coal powder, and coke. The belt scales were installed especially in the third phase of the technical reform project; also, in the new materials yard, XinYu has adopted nine units of MMI belt scales. Combined with a Siemens Milltronics BW500 integrator, the MSI offers powerful results. For example, the totalizer output function can be directly introduced into the DCS system for display, and it can communicate with the DCS system by the connected RS-232 or RS-485 interface.

Siemens MSI belt scales enable unified management and monitoring of energy and raw materials that are connected to the network through the whole factory. “Such features have greatly improved the measurement and management level of XinYu Steel,” states Qian Xhu Chen, Director of Automation. The application of Siemens MSI/MMI series of belt scales plays a key role in the custody transfer, energy saving, and cost accounting of XinYu Steel.

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