Raw material preparation: Scrap steel, pig iron and hot metal are used as raw materials, which are strictly screened and treated to ensure the purity of the molten steel and the accuracy of the composition.
Smelting: The use of electric arc furnace or converter for melting, by controlling the melting temperature and time, so that the raw materials are fully melted and evenly mixed. During the smelting process, operations such as slag ejecting and argon blowing at the bottom of the ladle are carried out to reduce the impurity content and improve the quality of the molten steel.
Refining treatment: The LF furnace is used for refining of molten steel to further remove harmful impurities and gases in molten steel and improve the purity of molten steel and the stability of chemical composition.
Vacuum treatment: Using VD or VOD furnace for vacuum treatment of molten steel, further reduce the content of hydrogen, oxygen and other harmful gases in molten steel, improve the quality of molten steel.
Continuous casting: Molten steel that has been refined and vacuum treated is cast into billets by a continuous casting machine. In the process of continuous casting, it is necessary to strictly control the temperature, drawing speed and cooling water amount of continuous casting to ensure the internal structure and mechanical properties of the billet.
Billet heating, heating and rolling: to a certain temperature, through the rolling mill, to form the required specifications of the steel pipe. In the rolling process, it is necessary to precisely control the rolling process and temperature to ensure the dimensional accuracy of the thickness, diameter and length of the steel pipe and the uniformity of the internal organization.
After heat treatment: according to the need of rolling of steel tube for normalizing and tempering heat treatment process, to improve its mechanical properties and processability.
Yield strength: approximately 250MPa, which is the maximum stress the material can withstand before permanent deformation occurs.
Tensile strength: between 400MPa and 550MPa, indicating the maximum tension that the material can withstand before breaking.
Plasticity: ASTM A36 carbon steel pipe has good plasticity. This means that large deformation can occur when stressed and it is not easy to break.
Weldability: Excellent weldability, suitable for a variety of welding methods. Such as gas tungsten arc welding, manual tungsten arc welding, submerged arc automatic welding, electroslag welding, etc.
NOMINAL PIPE SIZE | OD
(mm) |
NOMINAL WALL THICKNESS |
|||||||
DN | NB(inch) | ASME | SCH10 | SCH20 | SCH30 | STD | SCH40 | SCH60 | |
15 | 1/2″ | 21.3 | 2.11 | 2.41 | 2.77 | 2.77 | |||
20 | 3/4″ | 26.7 | 2.11 | 2.41 | 2.87 | 2.87 | |||
25 | 1″ | 33.4 | 2.77 | 2.9 | 3.38 | 3.38 | |||
32 | 1.1/4″ | 42.2 | 2.77 | 2.97 | 3.56 | 3.56 | |||
40 | 1.1/2″ | 48.3 | 2.77 | 3.18 | 3.68 | 3.68 | |||
50 | 2″ | 60.3 | 2.77 | 3.18 | 3.91 | 3.91 | |||
65 | 2.1/2″ | 73 | 3.05 | 4.78 | 5.16 | 5.16 | |||
80 | 3″ | 88.9 | 3.05 | 4.78 | 5.49 | 5.49 | |||
90 | 3.1/2″ | 101.6 | 3.05 | 4.78 | 5.74 | 5.74 | |||
100 | 4″ | 114.3 | 3.05 | 4.78 | 6.02 | 6.02 | |||
125 | 5″ | 141.3 | 3.4 | 6.55 | 6.55 | ||||
150 | 6″ | 168.3 | 3.4 | 7.11 | 7.11 | ||||
200 | 8″ | 219.1 | 3.76 | 6.35 | 7.04 | 8.18 | 8.18 | 10.31 | |
250 | 10″ | 273 | 4.19 | 6.35 | 7.8 | 9.27 | 9.27 | 12.7 | |
300 | 12″ | 323.8 | 4.57 | 6.35 | 8.38 | 9.53 | 10.31 | 14.27 | |
350 | 14″ | 355.6 | 6.35 | 7.92 | 9.53 | 9.53 | 11.13 | 15.09 | |
400 | 16″ | 406.4 | 6.35 | 7.92 | 9.53 | 9.53 | 12.7 | 16.66 | |
450 | 18″ | 457.2 | 6.35 | 7.92 | 11.13 | 9.53 | 14.27 | 19.05 | |
500 | 20″ | 508 | 6.35 | 9.53 | 12.7 | 9.53 | 15.09 | 20.62 | |
550 | 22″ | 558.8 | 6.35 | 9.53 | 12.7 | 9.53 | 22.23 | ||
600 | 24″ | 609.6 | 6.35 | 9.53 | 14.27 | 9.53 | 17.48 | 24.61 |