Steel Tube Handbook - 2018

100 Continuously cast steel blooms Steel blooms are the starting material for the production of seamless hot finished tubes and pipes. They are also used for the production of other metallurgical semi products by hot forming (rolling, forging, pressing). Dimensions and tolerances Dimensions and dimensional tolerances of steel bloom - square cross-section Table 44 Square side [mm] Tolerances [mm] Sidelong max* [mm] Cross-section area [mm 2 ] Weight [kg/m] Edge of the bloom [mm] 125 ±3 5 15 600 120,0 R = 3 mm ±1 mm 150 ±3 6 22 420 175,5 R = 3,5 mm ±1 mm 160 ±3 6 25 600 199,7 R = 4,5 mm ±1 mm 180 ±3 7 32 100 252,7 R = 5,5 mm ±1 mm 200 ±4 7 39 680 312,0 R = 6,5 mm ±1 mm 205 ±4 7 40652 319,5 R = 40 mm ±2 mm 225 ±5 9 50 170 394,8 R = 7 mm ±1 mm 280 ±6 11 76 662 615,0 R = 7,5 mm ±1 mm * Difference of diagonals of square Dimensions and dimensional tolerances of steel bloom - circular cross-section Tabuľka 45 Diameter [mm] Tolerances [mm] Ovality [mm] Cross-section area [mm] Weight [mm] 150 ±3 3 17 662 138,5 180 ±3 5 25 434 199,6 210 ±4 5 34 618 270,0 240 ±4 6 45 216 352,7 260 ±4 6 53 066 414,0 280 ± 6 7 61 575 475,0 Lengths The blooms are delivered in lengths of 4 000 – 10 000 mm with length tolerance of +50 mm. Straightness tolerance - 1% of length Obliqueness of front side - 5° Steel quality The steel is produced by electric process and is fully killed. The chemical composition of the steel is determined by standards and steel grades for individual groups of tubes. It is also possible to deliver blooms from other steel grades to meet specific customer requirements. Element content in % of weight C Mn Si Cr Mo Ni V S P Cu Sn Al Ti B Nb O N min 0,05 0,3 0,1 0,05 0,05 max 0 max max max max 0,005 max 1,2 2,5 1,3 2,5 1,1 3,4 0,8 0,035 0,035 0,40 0,040 0,050 0,050 0,001 0,050 0,035 0,010 Gases volume: O max. 0,0035% (35ppm), H max. 0,0050% (50ppm), N max 0,010% (100 ppm) - according agreement max. 0,008%. Conversion: a (%) x 10 000 = b (ppm). (But the using of ppm is in system SI non-permissible). Heat treatment, delivery condition and surface quality After casting the blooms are not heat treated, nor is the surface treated. Blooms are delivered according to technical delivery requirements. Testing Blooms are tested according to appropriate standards. Marking Blooms are stamped on their face. Markings include: heat number, steel grade code, stream number. In special cases blooms are marked with colour. Laying of blooms Square cross-section – in layers Circular cross-section – in special wooden pads or bound with steel strip. Certification Test report certificate in accordance with the specification: DIN 50049, EN 10204 – 3.1 or others.