Steel for special bar quality rounds (SBQs) (hot rolled round bars) is made in the Electric Arc Furnace with subsequent treatment in the Ladle Furnace. The produced steel is fully deoxidized with silicocalcium and aluminium finish to ensure a fine-grain structure. In case of special requirements to content of gas, sulfur and non-metallic inclusions steel is vacuum-degassed. To obtain low carbon concentrations steel is subjected to vacuum-oxygen decarburization (VOD process) in VD/VOD. Steel is bottom-poured into 3.45 t, 5.7 t, 6.5 t or 8.7 t ingot moulds.
Ingots are hot-charged into soaking pits with their subsequent rolling in 950/900 Specialty Bar Rolling Mill. The minimum ingot-to-bar reduction ratio is 6:1.
SBQs are anti-flake treated in the tunnel furnace (incomplete soft annealing cycle when the total rolled product heat treatment time depends on steel grade and equals to 22, 28 and 47-54 hours at temperatures of 680°C and 660°C). Such treatment method results in the rolled metal ferrite and perlite structure and excludes nonequilibrium structures (troostite, bainite, martensite).
Surface defects on billets are removed in centerless turning machines or abrasive-grinding machines. SBQs are straightened in oblique roll straightening machines. Bars are ground by peeling machines within diameter range of 75 to 260 mm to ensure rolled metal surface quality with roughness of Rz max 80 mm, Rz max 100 mm.
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INTERNATIONAL STANDARDS |
Steel grade groups |
Steel grade |
Diameter, mm |
Length, mm |
Standard ID |
Carbon steel |
(10XX, 13XX,
15XX, series)
1012, 1018, 1030, 1035, 1040, 1045 |
80-260 with 5 mm increment |
3200-6000 |
ASTM ?29/?29? |
(060AXX, 080AXX,
070MXX, 080MXX
150MXX series)
060?17, 070?20,
070?55, 080?40,
080?15
150?28, 150?36 |
80-260 with 5 mm increment |
3200-6000 |
BS 970 |
?1 |
80-260 with 5 mm increment |
3200-6000 |
BS 5892 |
LF1 (A105/AS105),
LF2 (A350/AS350) |
80-260 with 5 mm increment |
3200-6000 |
ASTM ?105/?105?,
ASTM A305/A350M |
C15?/C15R,
C22E/C22R,
?35E/C35R,
?45E/?45R,
C55E/C55R |
80-260 with 5 mm increment |
3200-6000 |
EN 10083-1 |
S355J0,
S355J2G3 |
80-260 with 5 mm increment |
3200-6000 |
EN 10025 |
Alloy steel |
(40XX, 41XX,
43XX, 61?? series)
4130, 4135,
4140, 4142,
4140?, 4142?,
4150, 4150?,
4340, 6150 |
80-260 with 5 mm increment |
3200-6000 |
ASTM ?29/?29?
ASTM A304 |
42CrMo4,
42CrMoS4 |
80-260 with 5 mm increment |
3200-6000 |
EN 10083-1 |
34 CrMo4 |
80-260 with 5 mm increment |
3200-6000 |
EN 10083-1 |
(86XX series)
8620, 8620?,
8720, 8720? |
80-260 with 5 mm increment |
3200-6000 |
ASTM ?29/?29?,
ASTM A304 |
16MnCr5,
16MnCrS5 |
80-260 with 5 mm increment |
3200-6000 |
EN 10084 |
251?58, 817?40,
655?13, 709?40,
605?36 |
80-260 with 5 mm increment |
3200-6000 |
BS 970 |
Pipe steel |
Gr E, Gr P, Gr B,
Gr D, Gr K,
X-44, X-45, X -42,
X-56, X-60 |
80-260 with 5 mm increment |
3200-6000 |
According to specifications |
St 10, St 15, St 20 |
80-260 with 5 mm increment |
3200-6000 |
According to specifications |
Sulfurous steel |
1117, 1141,
1144, 1132 |
80-260 with 5 mm increment |
3200-6000 |
ASTM ?29/?29? |
Stainless steel |
304, 304L,
310, 316,
316L, 321,
321L |
80-250 with 5 mm increment |
4000-6000 |
ASTM A304 |
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Mechanical properties/hardness: |
Mechanical properties are tested according to ASTM A370 and hardness is determined according to ASTM E10 using heat-treated specimens or as-delivered specimens.
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Hardenability (Jomini): |
Hardenability test is performed for alloy steel grades according to ASTM A255.
|
Macrostructure and grain size: |
Macrostructure is checked according to ASTM E381, austenitic grain size is determined according to ASTM E112.
|
Non-metallic inclusions: |
Non-metallic inclusions are controlled according to ASTM E45.
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Ultrasonic inspection: |
All SBQ rounds are subjected to ultrasonic inspection according to SEP 1921.
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Marking and packing: |
5-6 long finished rolled products are packed into max. 5 t bundles bound with wire rod in three places and six high-strength iron straps. Three weather-resistant plastic tags are fixed onto bundles (with a thermal stamping) specifying
- the customer,
- purchase order number,
- steel grade,
- heat number,
- size,
- bundle number and weight,
- country of destination etc.
One bar end face shall have colour ID code, the opposite end face shall be hot/cold stamped specifying heat number and steel grade, then a sticker is fixed.
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Dimensional tolerances: |
Diameter and ovality: |
According to ASTM A29/A29M, DIN EN 1060-3, BS 970 |
Length: |
+/- 100 mm |
Cut slope: |
Min. -7 mm |
Straightness: |
Min -3.175 mm per every 1525 mm of length |
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DOMESTIC STANDARDS |
Steel grade groups |
Steel grade |
Diameter, mm |
Length, mm |
Standard ID |
Carbon steel, common quality |
Ct0-Ct6cp |
80-275 with 5 mm increment |
3200-6000 |
GOST 380,
GOST 535,
GOST 2590,
GSTU 3-009 |
Carbon high-quality structural steel |
10-60 |
80-275 with 5 mm increment |
3200-6000 |
GOST 1050,
GOST 2590,
GSTU 3-009 |
Manganese steel |
15G-65G,
10G2-50G2 |
80-275 with 5 mm increment |
3200-6000 |
GOST 4543,
GOST 2590,
GSTU 3-009,
GOST 14959 |
Chromium steel |
15X-50X |
80-275 with 5 mm increment |
3200-6000 |
GOST 4543,
GOST 2590,
GSTU 3-009 |
Chromium-silicon- manganese steel |
25XGCA-35XGCA |
80-275 with 5 mm increment |
3200-6000 |
GOST 4543,
GOST 2590,
GSTU 3-009 |
Chromium-nickel steel |
20XH-45XH, 12XH3A-30XH3A, 12X2H4A-20X2H4A |
80-275 with 5 mm increment |
3200-6000 |
GOST 4543,
GOST 2590,
GSTU 3-009 |
Chromium- manganese steel |
18XGT-30XGT, 38XGM |
80-275 with 5 mm increment |
3200-6000 |
GOST 4543,
GOST 2590,
GSTU 3-009 |
Chromium- nickel steel with boron |
20XHP |
80-275 with 5 mm increment |
3200-6000 |
GOST 4543,
GOST 2590 |
Chromium-manganese-nickel with boron and titanium |
20XGHP, 15XGH2TA |
80-275 with 5 mm increment |
3200-6000 |
GOST 4543,
GOST 2590 |
Chromium- silicon steel |
33XC-40XC |
80-275 with 5 mm increment |
3200-6000 |
GOST 4543,
GOST 2590,
GSTU 3-009 |
Chromium- nickel- vanadium steel |
20XH4FA |
80-275 with 5 mm increment |
3200-6000 |
GOST 4543,
GOST 2590,
GSTU 3-009 |
Chromium- nickel- molybdenum steel, chromium-nickel-molybdenum-vanadium steel |
40XH2MA 45XH2MFA |
80-275 with 5 mm increment |
3200-6000 |
GOST 4543,
GOST 2590,
GSTU 3-009 |
Chromium-molybdenum steel, chromium-molybdenum-vanadium steel |
15XM-38XM, 40XMFA |
80-275 with 5 mm increment |
3200-6000 |
GOST 4543,
GOST 2590,
GSTU 3-009 |
Nickel-molybdenum steel |
20H2M |
80-275 with 5 mm increment |
3200-6000 |
GOST 4543,
GOST 2590,
GSTU 3-009 |
Bearing steel (incl. vacuum treated) |
ShX4, ShX15, ShX15CG, ShX20CG
??20?? |
80-235 with 5 mm increment |
3200-6000 |
GOST 801,
TU 14-1-3911,
TU 14-1-3680 |
Tool steel |
Y7-Y8A |
80-275 with 5 mm increment |
3200-6000 |
??TU 3833
(GOST 1435),
GOST 2590 |
Carbon pipe steel |
D, DB |
80-275 with 5 mm increment |
3200-6000 |
GSTU 3-009 |
Low alloy pipe steel |
36G2C-37G2C, 35G2F, 38XHM, B, X60, K55, 28XG2TP |
80-275 with 5 mm increment |
3200-6000 |
GSTU 3-009 |
Carbon pipe steel |
St37.0, St37.2, St52.0, St52.3, S355J2H |
80-275 with 5 mm increment |
3200-6000 |
GSTU 3-009 |
Boiler steel |
20, 12X1MF, 15GC, 15XM, 15X1M1F |
80-265 with 5 mm increment |
3500-6000 |
TU 14-1-1529 |
Laminated spring steel |
65G, 55C2-60C2, 60C2G, 60C2XA, 50XGA |
80-275 with 5 mm increment |
3200-6000 |
GOST 14959 |
Low-alloy steel |
09G2-14G2, 09G2C, 17G1C |
80-275 with 5 mm increment |
3200-6000 |
GOST 19281,
GOST 2590,
GSTU 3-009 |
High-alloy steel |
15X5M, 12X3GHMFBA, CP28 (28X3CHMBFA) |
80-265 with 5 mm increment |
5000-6000 |
TU 14-1-583,
GOST 2590, |
Stainless steel |
08-12X18H10T, 03X18H11, 08X18H10, 03X18H14M2, TP304, TP304H, TP304L, TP309S, TP316, TP316G, TP316L, TP317, TP317L, TP321, TP321H |
80-260mm |
5000-6000 |
TU 14-1?-1930
GOST 5632 |
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Mechanical properties/hardness: |
Mechanical properties are tested on heat-treated specimens or on as-delivered specimens according to GOST 1497. Brinell hardness is determined as per GOST 9012.
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Hardenability: |
Hardenability test for alloy steel grades shall be performed according to GOST 5657.
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Non-metallic inclusions: |
Non-metallic inclusions shall be controlled as per GOST 1778.
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Dimensional tolerances: |
Diameter and ovality: |
According to GOST 2590/GST 3-009 |
Length, mm: |
+50/-0.0 mm |
Cut slope, mm: |
Maximum 0.1 of diameter |
Straightness: |
According to GOST 2590/GSTU 3-009 |
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