ISO 16048 - Passivation of corrosion-resistant stainless-steel fasteners

Passivation of corrosion-resistant stainless Steel fasteners - ISO 16048


pickling bath
Type of
steela
chemicals Concentrations in vol%c Teplota c °C Exposure time in a fresh bathc min
A2
A3
A4
A5
C3 b
F1
HNO2 20 až 30 20 až 60 10 až 30
H2SO4 8 till 11 60
till 80
5
till 30
A1
C1 b
C4 b
HNO3 10
till 15
20 till 60 10
až 30
h2so4 8 till 11 60
till 80
5
atill 30
a Sort by steel ISO 3506-1, ISO 3506-2, ISO 3506-3 a ISO
3506-4
b Before pickling of steel connecting parts C1, C3 and C4, thermoformed must anneal to the softest soft annealed state and subsequently adjust the surface blasting, in order to reduce the risk of hydrogen embrittlement. Fasteners made toughening C1, C3 and C4, hot-formed and polished, shot peening is permitted to modify only the starting material.
c If necessary, the values permitted concentration
acid, the temperature and exposure times outside these ranges.


passivation bath
Type of
steela
chemicals Concentrations in volume % 0 Temperature0 °C Typical exposure time c min
A2, A3, A4, A5
C1
F1
HNO3 20
till 50
20
till 40
10
till 30
A1
C4
HN03 b 25
till 35
15
až 40
A1 HNO3 + Na2Cr207 . 2H20 c 15
till 25
C4 HNO3 + Na2Cr207 . 2H20 c 2
till 6
a Type of
steel podle ISO 3506-1, ISO 3506-2, ISO 3506-3 a ISO 3506-4
b Use
preferably the bath.
C Allows the addition of Na2Cr207 . 2H20 to minimize staining or etching of high carbon a
quick cutting of stainless steels.
Passivation must be verified
quality assurance system manufacturer. There is no known way of reference
test method passivation.