7freedom from defects

7.2.1

Subject to agreement with the purchaser, surface defects which cannot be dealt with as in 7.2 may be repaired by chipping or grinding followed by welding and inspection by a mutually agreed procedure such that,

• a) after complete removal of the defects and before welding, the thickness of the item is in no place reduced by more than 20 percent;
• b) welding is carried out by approved procedure by competent operators with approved electrodes and that the welding is ground smooth to the correct nominal thickness; and
• c) subsequent to the finish grinding, the item may be required to be normalized or otherwise heat-treated at the purchaser's discretion.

Table 1 Chemical Composition

(Clauses 5, 8.1 and 8.2)

NOTES

• 1 New grade designation system based on minimum yield stress has been adopted.

2 For semi-killed steel, silicon shall be less than 0.10 percent. For killed steel, when the steel is killed by aluminium alone, the total aluminium content shall not be less than 0.02 percent. When the steel is killed by silicon alone, the silicon content shall not be less than 0.10 percent. When the steel is silicon-aluminium killed, the silicon content shall not be less than 0.03 percent and total aluminium content shall not be less than 0.01 percent.

3 Steels of qualities A, BR, B0 and C are generally suitable for welding processes. The weldability increases from quality A to C for grade designation E 250 and E 275.

4 Carbon equivalent (CE) would be calculated based on ladle analysis, only. $\mathrm{CE}=\mathrm{C}+\frac{\mathrm{Mn}}{6}+\frac{(\mathrm{Cr}+\mathrm{Mo}+\mathrm{V})}{5}+\frac{(\mathrm{Ni}+\mathrm{Cu})}{15}$

5 Micro-alloying elements like Nb, V and Ti may be added singly or in combination. Total micro-alloying elements shall not be more than $0.25$ percent.

6 Alloying elements such as Cr, Ni, Mo and B may be added under agreement between the purchaser and the manufacturer. In case of E 600 and E 650 the limit of Cr and Ni, either singly or in combination, shall not exceed 0.50 percent and 0.60 percent respectively.

7 Copper may be present between 0.20 to 0.35 percent as mutually agreed to between the purchaser and the manufacturer. The copper bearing quality shall be designated with a suffix Cu, for example E 250 Cu. In case of product analysis the copper content shall be between 0.17 and 0.38 percent.

8 Incidental element — Elements not quoted in Table 1 shall not be intentionally added to steel without the agreement of the purchaser, other than for the purpose of finishing the heat. All reasonable precautions shall be taken to prevent the addition from scrap or other materials used in manufacture of such elements which affect the hardenability, mechanical properties and applicability.

9 Nitrogen content of steel shall not exceed 0.012 percent which shall be ensured by the manufacturer by occasional check analysis.

10 The steel, if required, may be treated with calcium based compound or rare earth element for better formability.

11 Lower limits for carbon equivalent and closer limits for other elements may be mutually agreed to between the purchaser and the manufacturer.

Table 2 Mechanical Properties

(Clauses 5, 10.3, 10.3.1, 11.3.1, 12.2 and 12.4)

NOTES

• 1 In case of product thickness/diameter more than 100 mm, lower minimum limit of tensile strength may be mutually agreed to between the purchaser and the manufacturer/supplier.
• 2 Bend test not required for thickness > 25 mm for grades E 300 to E 650. ' $t$ ' is the thickness of the test piece.
• 3 For sub-quality BR, impact test is optional; if required, at room temperature (25 ± 2°C).

1. 1MPa = 1N/mm² = 1MN/m² = 0.102 kgf/mm² = 144.4 psi.