THE STEELMAKING TRADITION WE TAKE PRIDE IN, CAN BE PRESERVED AND UPGRADED ONLY THROUGH DYNAMIC DEVELOPMENT.
Inventive spirit is our philosophy
We produce and develop steels for the future. Tool and special steels will continue to play the key role in the world. Our specialists focus on development of new, inventive steel grades which show remarkable mechanical and other properties. These steels are subjected to testing in our laboratories. Some of them are already available in the market. Development and research are part of rich tradition of the company Metal Ravne and they represent one of our strategic areas. In development of new steel grades, we work closely together with universities. But our main activity concentration lies on the field of steel production, casting, and hot and cold plastic deformation of steel.
We have several test laboratories for testing of our steels. They are certified by proper institutions. Laboratories run inspection and testing of steels from our production.
Here, heat treatment of specimen for metallurgical laboratories is carried out. Heat treatment is implemented in conventional electric hardening and tempering furnaces and in a vacuum furnace. We perform the following heat treatment services:
- all types of annealing,
- quenching, tempering,
- case hardening,
- testing of steel hardenability (Jominy test, sensitivity-to-grain growth hardenability test),
- hardness testing according to Brinell (HB),
- hardness testing according to Rockwell (HRC),
- hardness testing according to Vickers (HV),
- microhardness testing according to Vickers (HV).
Our mechanical laboratory performs mechanical testing on conventional and instrumented machines. The following tests are carried out:
Tensile test: Test piece is subjected to tension in longitudinal direction. Tensile test is used to determine: force, Re yield stress, Rm tensile strength, stress, A elongation and Z contraction.
Compression test: It is used to test material behavior if influenced by an external force causing compression and test piece shortening. Compression test is used to determine compression strength.
Bending test: Test piece is placed on two supports and loaded in the middle which prevents rising of compression faster than 30 N/mm2 per second. Bending test is used to determine: force, bending angle, deflection and bending strength.
Shear test Shear test is not performed very often. Practically, we cannot reach a clean tangential stress with a shear because this would require extremely thin blades. In practical shear implementation, deflection is the result of a shift and with this a pair of forces. Shearing device usually integrates two blades and is built for stretching in a tensile testing machine.
Impact test. Materials can show a tough or brittle fracture. Impact toughness (by a notch) is a special property of material showing its behavior in a deformation with accelerated, impact load by the notch. Testing is made on a machine with oscillating pendulum hammer (Charpy machine). The pendulum hammer begins to oscillate from a certain height and it hits against a notched test piece in its lowest position, and fractures it. Here, we test: DVM, ISO-V, ISO-U, Messnager and test pieces without a notch.
ZF method: Brugger’s method or testing method for toughness of case-hardened materials (ZF method) is used to establish impact characteristics of materials. Force necessary to break a test piece is defined depending on time.
Toughness testing according to ŽR method: The ŽR method for testing of toughness involves testing of maximum force of fracture which is for the evaluation of toughness of solid tool steels much more justified from the practical view of tool applicability than testing of labour spent on fracture of test piece.
Fatigue test: This test is used to establish behavior of material under fluctuating loads. Stress endured by material can cause its destruction if repeated several times. In addition to the size of stress, the number of repeated stresses also has impact upon destruction. We say that material becomes fatique and this results in fatique fracture. Dynamic permanent strength is the major deviation of stress oscillating around the central stress endured lots of times without rupture and without additional deformation. We use a high-frequency pulsator device for permanent oscillation testing.
Fracture mechanics. Fracture mechanics deals with analyzing of crack development in brittle and quasi brittle bodies. The name fracture mechanics has a double meaning. In its narrower sense, it refers to a research of crack development conditions. In its broader sense, however, it also includes a part of material resistance which refers to the end phase of deformation process under the influence of impact. Therefore, fracture mechanics analyses very important issues of resistance and construction fracture.
Metallographic laboratory analyses microstructure characteristics of steel which are significant for steel properties and its applicability. The basic microstructure properties are: type of microstructure, type and distribution of microstructure components, the size of crystal grains and precipitates, the size and type and distribution of non-metallic inclusions, cracks, micro-shrinkages, segregations and other defects in steel. Metallographic testing is divided into macroscopic and microscopic testing. With the former one, we observe structure with unaided eye and/or under magnifying lens up to 10x magnification, and with the second one up to 2000x magnification using optical microscope and/or scanning electron microscope (SEM) up to 180 000x magnification.
In laboratory, the following testing is carried out:
Macro defects are detected in materials like: surface defects on products (lamination, rolling or forging cracks, grinding cracks), defects originating from casting (macro inclusions, segregations, porosity, flakes) and defects from plastic processing of steel (cracks, cross-shaped crack). Before testing, samples have to be properly prepared by grinding, and cold and/or hot macro etching. The following standards are used to evaluate macro defects:
- evaluation of etching plates according to ŽR table,
- Baumann printing of sulphur distribution,
- macro etching and evaluation according to SNO 1710 and MIL ST 1459 A,
- checking of ground bar surface,
- evaluation of macro-etch testing specimen according to ASTM A-604,
- evaluation of macro-etch testing specimen according to ASTM E-381,
- evaluation of macro-etch testing specimen according to ASTM A-561,
- evaluation of macro-etch testing specimen according to GOST 801,
- evaluation of macro-etch testing specimen according to Böhler table.
Microscopic testing is made according to comparative tables and standards in our laboratory:
- non-metallic inclusions according to ASTM E-45,
- non-metallic inclusions according to GOST 801,
- non-metallic inclusions according to DG,
- non-metallic inclusions according to SAE J422,
- non-metallic inclusions according to NF A04-106,
- non-metallic inclusions according to DIN 50602 method M,
- non-metallic inclusions according to DIN 5062 method K,
- non-metallic inclusions according to ISO 4967-98 method A,
- non-metallic inclusions according to SEP 1572,
- austenitic or primary grain according to ASTM E-112,
- hypoeutectoid or secondary grains according to ASTM E-112,
- grain size according to McQuaid – Ehn method,
- size of austenitic grain according to Snyder – Graff,
- grain size with twin lamellas according to ASTM E-112 table III,
- grain size according to JUS C.A3.004,
- grain size in cast steel 12Mn,
- grain size according to DIN 5061 and ISO 643,
- distribution of carbide segregations in high-speed steel according to ŽR table,
- size of carbides in high-speed steel according to ŽR table,
- banded microstructure of carbide segregations in tool steels according to SEP 1615 table,
- size of carbides in OCR 12 steel according to ŽR table,
- distribution of carbide segregations in OCR 12 steel according to ŽR table,
- distribution of carbide segregations in OCR 4 steel according to DG table,
- distribution of carbide segregations in OCR 4 according to GOST 801 table,
- determination of carbide nework according to GOST 8233 table 5,
- determination of carbide network according to GOST 801 table 6,
- distribution of chrome carbides in PK 5 steel (W.Nr. 1.4116),
- distribution of carbides according to ISAN table,
- distribution of carbides according to Bohler table,
- microstructure as annealed in steel for ball bearings according to DG,
- evaluation of microstructure as annealed in steel for ball bearings according to GOST 801,
- evaluation of microstructure according to SEP 1520-78,
- evaluation of overheating in OCR 12 steel according to ŽR table,
- general evaluation of microstructure as hardened&tempered,
- general evaluation of decarburization depth,
- evaluation of annealed microstructure according to Böhler table,
- evaluation of annealed microstructure according to Chrysler Corporation table,
- determination of the share of alpha phase in stainless steel according to GOST 11878,
- determination of alpha – gamma phase ratio in construction steel for special applications,
- annealed microstructure according to CNOMO Nr. E01.17.221.N,
- evaluation of annealed microstructure according to NADCA table,
- evaluation of microstructure according to FAG table,
- evaluation of banded microstructure according to TEKSID 9.562.10/25 AL.L.2,
- evaluation of annealed microstructure according to SEP 1614,
- evaluation of banded microstructure of case-hardening steel according to ŽR table,
- evaluation of banded microstructure of steel for ball bearings according to GOST 801 table,
- evaluation of banded microstructure according to GOST 5640 table,
- evaluation of banded microstructure of Cr-Ni steel according to DG 3.05.0 table,
- evaluation of carbide segregations in die steel,
- evaluation of banded microstructure in steel according to IVECO 15-0261 steel,
- banded microstructure according to NADCA table.
Laboratory for corrosion
Corrosion testing is part of our regular steel quality control. We use cold test (at 20 °C) and hot test (over 20 °C). Acid, base and salts are used as reagents. We perform the following test of corrosion resistance of steel:
- testing of stainless steel for resistance against intercrystalline corrosion according to ASTM A-262,
- testing of steel for resistance against intercrystalline corrosion according to DIN 50914,
- corrosion test according to ICK 01-89.
Laboratory for X-ray structural analysis
We perform the following testing with X-ray diffractometer:
- we define the contents of alpha phase in austenitic steel,
- we define the contents of residual austenite in steel,
- we define phase composition of steel,
- we study effects that develop during heat treatment of steel,
- we define composition of refractory materials, oxides and corrosion products.
We use dilatometer to establish:
- transformation points in steels (Ac, Ar, Ms, Mf , Bs),
- we make continuous CCT diagrams,
- we make isothermal TTT diagrams,
- we test linear expansion coefficients,
- we define dimensional changes due to structural changes during heat treatment,
- we define tempering effects.
Laboratory for scanning electron microscopy (SEM)
Scanning electron microscope and energy dispersion spectrometer EDS are used for the following services:
- routine microscopy of massive and thin samples, and thin films on substrata,
- EDS microanalysis of phases in microstructures and on fracture surfaces,
- EDS microanalysis of phases in thin samples,
- EDS microanalysis of phases in multi-component thin films on substrata,
- SEM and EDS analysis of ecological samples,
- SEM and EDS analysis of deposits, corrosion products and pulver materials,
- quantitative analysis of microscopic images,
- SEM fractography,
- complete analysis of fracture surfaces (establishing the cause of fracture),
- evaporating of samples with Au, Ag, Pb and Cu,
- cutting hard materials with diamond cutter (up to bottom thickness of 0.5 mm),
- preparation of replicas on samples and finished machine components,
- preparation of metallographic specimen on large components and evaluation of microstructure,
- preparation of metallographic specimen from NE-materials (Pb, ceramics, hard metal alloys, diamond particles in metal binding agent),
- product problem solving,
- advising in designing new laboratories.
Laboratory for chemical analysis
This laboratory is responsible for quality in the field of chemical analyses. It includes a workshop for laboratory preparation of specimen and the main chemical laboratory. The following analyses are made:
- all sorts of steel (cold- and hot-work steel, plastic mould steel, stainless steel,
- Ni and other alloys,
- PM steel and alloys.
Workshop for sampling