OREANDA-NEWS. June 23, 2008. Steel grinding balls may be considered the key product of Gurievsk Metallurgical Plant that has been specializing in their fabrication over the last 75 years. It was GMP that in 80’s served the basis for development of GOST for this product that is still effective in Russia. The plant  keeps in pace with time: it is an acknowledged leader of the Russian grinding bodies market, it produces about 6 ths t of balls per month and accounts for 16 – 23% of the Russian market.

The total capacity of GMP ball-rolling mills is 200 ths t per year that makes the company potentially the largest steel balls manufacturer in Russia. According to the Deputy General Director for rolled sections sales of ESTAR Trading House Sergei Romanov by 2012 the output is planned to increase from 6 to 10 ths t of balls. However in the current situation, when customers have actually an unlimited choice of products from the world’s largest producers the first priority task is the increase of quality. To make the production technology widely-known the GMP management held on May 20 - 22 a special presentation of grinding balls of higher volume hardness, wherein the potential and current customers were shown the entire process of production and informed on peculiar features of the steel grinding balls production technology applied not only in Russia, but abroad as well. According to the organizers of the presentation, the  customers’ opinions will help to adjust products in the future with regard to their wishes.

Back in 2004 the plant’s  specialists faced a challenge to reach the world’s level of balls production. To achieve this, the experience of the world’s largest producers was examined: the plant’s  specialists brought foreign-made balls and tested them in their labs. They found out that the secret of their strength is in a thorough heat treatment. This became the key direction that Gurievsk specialists have chosen for modernization: they introduced a multistage heat treatment technology for the balls.

Within the frame of the program for further product quality enhancement GMP purchased new equipment which has no analogues in Russia. Thus, in October of 2007 a temper furnace was commissioned. As a result GMP became the first steel works in the country, wherein a backing technology was applied. This technology has enabled considerable growth of balls quality.

According to experts, today the GMP ball-rolling products exceed qualitative specifications of the Russian GOST.

The “truncated” technology that has been applied by the majority of steel works and designed for the balls’ strength increase in the course of “self-tempering” alone does not suit  manufacturing of fundamentally new properties of the products. To produce equilibrium one-phase ball structure the quenching should be followed by a low temperature tempering relieving thermal and phase stresses. As a result a ball obtains quite a different structure and different qualities: with the same composition and non-metal inclusions in steel the ball has impact and abrasion resistance, respectively, 3.5 and 1.5 higher than the ball fabricated with a common technology. It is the temper furnace commissioned in October of 2007 that enables the classical heat treatment.

Of course, a sophisticated production facility cannot exist without application of the up-to-date scientific research. That is why the project involved scientists of special research institutes of the Urals and Siberia. The research developed at GMP in cooperation with the scientists and purposed for the enhancement of grinding bodies quality is still on. According to Alexander Studenov, GMP Managing Director, the application of new equipment has already enabled the plant  to come closer to the world standards.

Another problem that the process engineers of the plant  are working on is the improvement of steel chemical composition as it is a key to production of high quality balls. According to Igor Matveev, Technical Department Manager, tougher requirements to the ball steel is one of the basic trends in industry. As a result the balls fabricated of waste rail steel do not meet customers’ requirements. This is especially the case with the cement production and non-ferrous ores processing, where the balls should be strong, hard and quenched through, not at the surface only. It should be noted that the iron-ore industry will very soon have the requirements similar to the cement production industry, and this trend is quite evident.

To enhance steel quality, GMP applies microalloying that allows for optimization of its chemical composition. To achieve this in May the plant  purchased new equipment for the central plant  lab and express lab of Siemens-Martin and ball-rolling shops, such as desktop optical emission spectrometers ARL QuantoDesk. These will give an opportunity to accelerate chemical testing of steel, cast iron and final rolled products and to achieve more accurate data on metal chemical composition. Previously chemical tests in the express lab of the Siemens-Martin plant  were run with the help of AUS-7644I express analyzer that allowed for checking sulfur, carbon, manganese and phosphorus content. In addition to these data the new spectrometer makes it possible to receive additional data on the content of silica, copper, nickel, chromium, titan, vanadium, zinc and aluminum. It should be noted that the new instrument enables research in the course of melting: from steel melting to tapping. Immediate test results make it possible to make corrections of the steel chemical composition in the process of melting, and hence, to receive steel of higher quality and to minimize waste.

One of the latest acquisitions for the ball-rolling express lab is a Medium Delta automatic orbital cutter at at price about 1,700,000 rubles. Unlike the already available SV-EI-1 Electrospark Discharge Machine that enables preparation of a specimen for a ball structure analysis within 6 – 8 hours, Medium Delta reduces this procedure to 10 – 20 minutes subject to the diameter size. This accelerates the receipt of the data on the hardness of the steel grinding body center as well as the volume hardness, hardness penetration and macrostructure. As a result we have an opportunity to test specimens from each lot of products. It means that customers may be 100% sure of grinding balls high quality as Medium Delta timely reveals any defect, and the specialists of the plant  have an opportunity to remove it promptly, change hardness settings and coordinate shipment of products complying with the customers’ requirements.

Besides, customized equipment has already been designed and is now being installed for impact resistance, abrasion and fatigue strength tests in accordance with Goldfields Lab (Republic of South Africa) technology.

Quality tickets introduced since April 1, 2008 at GMP provide for additional quality control in case of process violation and reduction of quality of the products. The objective is to create a standardized system of supervision over adherence to the process procedures. The ticket system has been introduced at all iron industry facilities back in 1986, so its efficiency was elaborated and verified by years of application. According to experts the ticket system will increase the level of personal responsibility of each employee for the results of his labor and will reduce the number of violations of process procedures.

“We believe that through the enhancement of our products’ quality we shall be able to keep our clients as well as to attract new ones including those who were not satisfied with our quality in the past - cement plants, gold and copper producing facilities”, Sergei Romanov says. “Our balls have a longer life, and waste has been considerably reduced. This is also true for other types of rolled products as GMP also produces angle and channel iron, and other rolled sections.”