Moulds

Coquilles for casting high-quality metal samples

The introduction of new coquilles and samples reduces the duration of melting and analysis of samples, the consumption of expensive alloying additives, increases the accuracy of the analysis to the requirements of GOST for this brand of alloy.

1. It is known that metallurgists get the greatest economic effect when smelting alloys that meet the requirements of GOST for chemical composition for the minimum melting time with the content of expensive alloying additives at the lower permissible limits. According to the literature, foreign researchers have developed a number of technical means to achieve these goals:

• multi-channel optical emission spectrometers and roentgenofluorescence for the complete sample analysis for all the elements in accordance with GOST for small /3-4 min./ time; spectrometers equipped with computers and software
• the software performs quick calculation additions of alloying element according to the specification for this grade of alloy
• technical tools for fast feed, weighing and entering into the melting furnace alloying elements
• coquille for casting samples of the "fungus" type during melting, constant in shape, weight and size, for a minimum cooling time of the casting /without quenching/ using special machines for fast and standard sharpening of the analyzed sample surface

2. Casting samples of the "fungus" type in the coquille provides the following advantages:

• fast cooling of the casting bush in 2-3 minutes. No quenching of high-carbon alloys with cooling of the sample by blowing cold air or in water (for non-ferrous alloys)
• the constancy of mass, shape and size of the sample, regardless of the brand of alloy
• the persistence of structural and chemical homogeneity of the analyzed areas of the sample
• no need for cutting samples from a large cross-sections, which excludes the operation of powerful machines abrasive, strong heating of the sample after cutting, the sample cooling after cutting (total loss of time for cutting and cooling of the samples according to GOST 7565 can be 6-8 min.)
• the possibility of using pneumatic mail for accelerated delivery of samples to the laboratory
• complete absence of contamination of the sample material with the coquille material, since the surface of the coquille in contact with the melt is provided with a plasma coating-a substance having a high melting point (2900°C), i.e. the sample is representative
• convenience of marking with a shock method
• high operational convenience when sharpening samples on abrasive, milling and turning machines of the company "Herzog" (samples, SOPs and GSO are recommended to be sharpened on milling and turning machines)
• high operational convenience of installation and reliable fixing of the sample in the vise and on the table of the USHT-4 tripod with a holder, in the cartridges of X-ray spectrometers, on the table of vacuum domestic and imported spectrometers with a sample holder (see drawing DP-168.00 SB)
• the convenience of selecting chips for arbitration chemical analysis with a milling cutter,cutter or drill < br> the possibility of casting blanks of standard samples of the enterprise (SOP) of a given chemical composition into the coquille
• the possibility of processing on the machines of the company "Herzog" and the special station of the design of CJSC "Spectral Laboratory"
• the sample of the "fungus" type meets the requirements of GOST 7565 by weight. According to this GOST, the sample for spectral analysis should have a mass of 0.06 kg. A sample of steel of the "fungus" type with a diameter of 40 mm. and with a thickness of 8 mm. it has a mass of ~0.1 kg

3. The listed advantages of the "fungus" type sample allow you to get a real economic effect due to:

• reduction of melting time by 10-15% due to the absence of time losses for waiting for the analysis results, since the time for preparing samples for analysis is reduced by 6-8 minutes.
• reducing the melting time results in greater energy savings
• improving the accuracy and reliability of the analysis provides savings in the consumption of alloying additives and significantly reduces the likelihood of melting defects in chemical composition 4. The listed advantages of the "fungus" type test provided it with wide distribution in the USA, Western Europe and Japan. In the practice of metallurgists of the Russian Federation and the CIS, the use of samples of the "fungus" type is extremely rare. None of the enterprises of the Russian Federation and the CIS produce mass-produced and do not advertise coquilles for casting samples of the "fungus" type. In 1976, for the first time in Leningrad, at the Kirov Plant, a coquille was introduced (used to this day) for casting disc samples of various steels, which are analyzed during melting on the DFS-51 spectrometers of JSC LOMO. In the early 80-ies, the author developed and implemented at the plant "Techpribor" g. Leningrad coquille for casting disc samples from aluminum alloys, which is still used today.

5. Currently, five new types of coquilles for casting samples of ferrous and non-ferrous alloys have been developed, tested and can be supplied through CJSC "Spectral Laboratory" in St. Petersburg:

• metal coquille with plasma coating for casting samples of all grades of steel and alloys based on iron, nickel, cobalt, etc., providing the production of samples of the "fungus" type A 40 mm and 8 mm thick with a central protrusion A12 mm and 15 mm thick on the non-working part of the sample; the weight of the coquille is 4.6 kg, the sample is ~0.1 kg
• metal coquille with plasma coating for casting samples of all arches of bleached cast iron " A 40 mm and 4 mm thick with a central projection A12 mm and 15 mm thick on the non-working part of the sample. Together with the sample, two thin plates with a thickness of 0.8 mm and an area of 3.5 cm square are cast. These plates are easily separated from the casting with pliers and, if necessary, sent to the chemical laboratory for arbitration analysis of the casting. Bleached cast iron is a very brittle material and is easily crushed in a mortar. This technique speeds up the chemical analysis and simplifies the sampling of very hard material-bleached cast iron
• metal coquille with plasma coating for casting samples of all grades of non-ferrous alloys based on aluminum, copper, magnesium, lead, tin, silver, etc. 40 mm thick and 8 mm thick. The weight of the coquille is 4 kg. A "fungus" type sample with a protrusion in the central part of the sample of 12 mm and a thickness of 15 mm on the non-working part of the sample. The spigot can be used for chip selection for arbitration chemical analysis of the sample
• metal coquille with plasma coating for simultaneous casting of four rods of 0.8 mm and 72 mm length from any non-ferrous alloys for the determination of impurities on air spectrometers of the "MFS-8" SL type with a UGE–4 generator (it is known that the sensitivity of the spectral determination of impurities increases significantly if both arc/spark electrodes are made of the same material), other elements can also be determined together with impurities
• metal coquille with plasma coating for simultaneous casting of three samples: one of the "fungus" type A 40 mm and 8 mm thick and two rods A8 mm and 70 mm long for analysis on various measuring instruments

6. For each coquille, the Customer is provided with a passport containing

• scope of application of the coquille
• a description of the advantages of the coquille and the sample, as well as a version of the flow chart/instructions for casting the sample of this brand.

The map contains working drawings of the coquille and the sample holder of the "fungus" type (coquilles are not supplied without a passport).