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astm a556 / a556m – 96(2012) standard specification for seamless cold-drawn carbon steel feedwater heater tubes
astm a556, asme sa 556 is a common standard specification for seamless cold-drawn carbon steel feedwater heater tubes. it covers minimum-wall-thickness, seamless cold-drawn carbon steel tubes including bending into the form of u-tubes. in order to increase the heating area and prevent heat from being taken away by cooling water in the condenser, the u-bending design is essential. the steel pipe is used for making a water cooling wall of the power plant boiler, it can effectively eliminate the steam film on the inner wall of the steel tube and improve the thermal efficiency of the furnace wall. there are three grades for this specification: grade a2, b2, c2, and among them, b2 and c2 are commonly used.
description:
outside diameter: 12-40mm
wall thickness: 1-4mm
length: max length 27 meters
method: cold drawn
delivery condition: nbk, bright, u bending.
comparison table of international standards
astm | bs | din | nfa | jis |
a210 a1 | 3602 pt1 | 17175 | a 49215/9 | g 3461 |
a566 b2 | st 430 cat2 | st 45.8/1 | t 442 b/f | st b 410 |
210 gr. c | 3606 | 17175 | - | - |
a 566 gr. c2 | st 440 cat. 2 | 17 mn 4 | - | - |
chemistry composition
element | composition, % | ||
grade a2 | grade b2 | grade c2 | |
carbon, max | 0.18 | 0.27 | 0.30 |
manganese | 0.27–0.63 | 0.29–0.93 | 0.29–1.06 |
phosphorus, max | 0.035 | 0.035 | 0.035 |
sulfur, max | 0.035 | 0.035 | 0.035 |
silicon, min | .... | 0.10 | 0.10 |
mechanical properties
grade a2 | grade b2 | grade c2 | |
tensile strength, min, ksi [mpa] | 47 [320] | 60 [410] | 70 [480] |
yield strength, min, ksi [mpa] | 26 [180] | 37 [260] | 40 [280] |
elongation in 2 in. or 50 mm, min, % (longitudinal) | 35 | 30 | 30 |
hardness requirements
grade a2 | hr b 72 |
grade b2 | hr b 79 |
grade c2 | hr b 89 |
tolerances
tolerances according to specification or according to agreement. standard tolerances are:
hot finished | od +/- 1% | wt +/-12.5% |
cold finished | od +/-0.75% | wt +/-10% |
