1.4460 AISI 329 Corrosion resistance

The steel grade 1.4460 AISI 329 is a stainless, acid resistant, duplex steel with improved machinability. Since the steel is machinability improved, it is suitable for production of details with comprehensive machining. The steel has very good corrosion resistance particulary in chloride-bearing environments and is extra resistant to pitting corrosion, crevice corrosion, stress corrosion cracking and corrosion fatigue. It also has high strentgth and toughness.

Corrosion resistance

329 has a Pitting Resistance Equivalent (PRE) of ≥31.

329 has very good resistance to stress corrosion cracking in chloride environments. The grade has also good resistance to general corrosion in acidic media, thanks to the high chromium content and alloying with molybdenum.

Microstructure

In the solution annealed and quenched condition Sanmac 329 has an austenitic-ferritic microstructure, which is free from grain-boundary carbides and intermetallic phases. The ferrite content is 55 – 75%.

Good machinability, weldability and formability

1.4460 is possible to weld and do not need to be welded with welding consumables similar to that of the parent one. The steel shall be welded as austenitic material with as low heat input as possible. It can be both cold- and hot formed. The steel is easier to machine and it has significantly better machinability, but slightly worse corrosion resistance than 1.4462.

ANNEALING

Parts should be solution annealed between 1870/2010ºF (1020/1100ºC) and water quenched. Approximately equal amounts of austenite and delta ferrite will be formed after solution annealing.

MACHINABILITY

This grade is quite difficult to machine, perhaps more so than the normal 18/8 austenitics. Type 309 has only about 50 percent of the machinability index of type 316. It is recommended that the best possible machines and tooling be used for machining of parts made from this grade.

Smelting Option

1 EAF: Electric Arc Furnace

2 EAF+LF+VD: Refined-smelting and vacuum degassing

3 EAF+ESR: Electro Slag Remelting

4 EAF+PESR: protective atmosphere Electro Slag Remelting

5 VIM+PESR: Vacuum induction melting

Forming Option

1 Hot rolling process

2 Hot Forging: Electro-hydraulic; High-speed-hydraulic; Oil-hydraulic; Precision-forging

Heat-treatment Option

1 +A: Annealed (full/soft/spheroidizing)

2 +N: Normalized

3 +NT: Normalized and tempered

4 +QT: Quenched and tempered (water/oil)

5 +AT: Solution annealed

6 +P: Precipitation hardened

Suface Option

1 Black Surface

2 Grounded: Bright but rough ; Not precision

3 Machining for plate: Bright and precision; Little turning scar

4 Peeled/Turned: Bright and precision; Little turning scar

5 Polished: Very Bright and precision size; Not turning scar

Other Services

1 Cutting: Small pieces

2 CNC Machine: Produce as your drawing

3 Package: Bare/Nylon/Canvas/Wooden

4 Payment:T/T, L/C, O/A(request credit)

5 Transport:FOB/CFR/CIF/DDU/DDP (train/ship/Air)

typical applications areas for 1.4460 are:

Propeller- and PumpshaftingPump- and ValvepartsPistonsStirrersBoltsNuts