What if the bend radius is below the minimum?

Clause 5.1.3.2 then asks for heat treatment, or for ageing impact tests at the strain concerned to show the impact properties are not harmed, and a surface inspection showing no cracks.

Why does the limit depend on Ceq for TMCP steel?

Table 5.1.3.4 has separate rows for TMCP steel with a carbon equivalent above 0.38 % and at or below 0.38 %. The lower carbon equivalent allows a higher surface temperature.

Why does the tool say the grade is not in the table?

The table covers AH, DH and EH steels only. For other grades the rule gives no number, so the tool does not make one up.

Engineering tool

Cold bending and line heating limits

Three checks from the CCS Rules for forming hull steel plate: the smallest inside bend radius for cold forming, whether forming above 650 °C needs mechanical tests, and the highest surface temperature allowed when fairing by line or spot heating.

Cold forming

Plate thickness (mm)Inside bend radius (mm)Member carrying high stress (special member)

The radius meets the minimum of 90 mm (4.5 × thickness).

Your radius is 5.0 × the thickness.

Forming temperature

Forming temperature (°C)Line or spot heating

Line or spot heating (fairing)

Steel gradeProduction routeCooling after heating

The surface temperature must stay below 650 °C.

Table 5.1.3.4 row: conventional AH, DH and EH steel, or TMCP AH36 to EH36 with Ceq above 0.38 %.

What this tool covers

CCS Rules for Materials and Welding 2021, Part 3 Chapter 5, clause 5.1.3: the inside bend radius of 4.5 times the thickness (10 times for members under high stress), the 650 °C limit for forming without tests, and Table 5.1.3.4 for the surface temperature in line or spot heating of AH, DH and EH steels of grades 32 and 36.

What it does not cover

Table 5.1.3.4 does not list normal strength steel, FH grades or the 40 series, so the tool gives no limit for them. It does not give heating times, cooling rates or flame settings, and it does not replace the yard's forming procedure.

Questions about forming limits

What if the bend radius is below the minimum?: Clause 5.1.3.2 then asks for heat treatment, or for ageing impact tests at the strain concerned to show the impact properties are not harmed, and a surface inspection showing no cracks.
Why does the limit depend on Ceq for TMCP steel?: Table 5.1.3.4 has separate rows for TMCP steel with a carbon equivalent above 0.38 % and at or below 0.38 %. The lower carbon equivalent allows a higher surface temperature.
Why does the tool say the grade is not in the table?: The table covers AH, DH and EH steels only. For other grades the rule gives no number, so the tool does not make one up.

Source

The clauses and Table 5.1.3.4 were read from the page images of the CCS Rules for Materials and Welding 2021 (page 3-54 of Part 3). This is the CCS rule, not an IACS unified requirement. Your society's own rules govern.

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