Alloy No. 20 steel (marketing department of Shanghai HY Industry Co., Ltd)
Alloy No. 20 is a solid-solution-strengthened iron-nickel-based alloy with extremely high corrosion resistance to sulfuric acid. It is widely used in high-concentration and high-temperature sulfuric acid environments. It is a corrosion-resistant steel among stainless steels. In addition, Alloy No. 20 also has excellent intergranular corrosion resistance and stress corrosion cracking resistance.
Material grades and equivalents：
Grade name |
Note |
Alloy 20 |
Alloy No. 20 |
UNS N08020 |
ASTM A240/B463 |
F20 |
ASTM A182 |
CN7M |
ASTM A351 |
Carpenter 20 CB 3TM |
Carpenter Technology Corporation |
2.4660 |
DIN |
NAS 335X |
NIPPON YAKIN |
0Cr20Ni35Mo3Cu4Nb |
GB previously |
NS 143 |
GB/T 15007-1994 |
NS 1403 |
GB/T 15007-2008 |
chemical composition
C |
Si |
Mn |
P |
S |
≤0.07 |
≤1.00 |
≤2.00 |
≤0.045 |
≤0.035 |
Ni |
Cr |
Mo |
Cu |
Nb |
32~38 |
19~21 |
2.0~3.0 |
3.0~4.0 |
8×C~1.00 |
▲Above is the American standard data, and the GB standard has lower phosphorus and sulfur content (P≤0.030, S≤0.030)
▶Plastic workability
-
Can be treated the same as ordinary austenitic stainless steel.
▶Weldability
-
Welding is the same as quasi-austenitic stainless steel, TIG welding, MIG welding and manual arc welding can be used. Due to the Nb content, heat treatment should be minimized. Please use ER320, ER320LR as solder.
▶Machinability
-
Machinability is about the same as standard austenitic stainless steels. It is recommended to use high-speed steel tools or super-hard alloy tools for cutting. It is advisable to slow down the advancing speed and increase the cutting depth.
▶Heat treatment
-
The stable heat treatment condition is 925~1010°C (as specified in ASTM A480/A480M), and it must be quenched after heat treatment.
▶Pickling
-
A mixture of nitric acid and hydrogen fluoride is used for pickling, and the pickling conditions are the same as those of SUS 304 same.
▶Use
-
Sulfuric acid equipment, various chemical and petrochemical equipment.
