I daily machine S80, S130, S143 corrosion resistant steel. Can anyone
provide information on these steels i.e. which group they fall into (300 or
400 series), hardness values & whether they are austenitic or marstenitic. I
can't seem to nail down any info apart from the following:
S80 = AMS 5828D/ AISI431
S143 = AMS 5659/ AISIS1550
S130 = AMS QQ-S-783 CLASS 321A/ AMS 5646/ AISI347
I'm really trying to tie up the materials with the speeds and feeds printed
in the Machinery's Handbook Pocket Companion.
Also why can I not find any info on the spec themselves, hardly anywhere
recognises the 'S' spec. Any thoughts?
S143 is a precipitation hardenable stainless steel. The grade is known as
FV520B and contains about 0.05% Carbon, 14% Cr, 1.5% Mo, 5% Ni and 1.5% Cu.
This is the same basic steel as S144 and S145 aswell the only differnce
being the heat treatment given and thus the properties achived. S144 is
stronger then S143 but has lower toughness. S145 takes this a step further
but there is a significant loss of toughness. This is primarily a British
grade (FV - Firth Vickers, ex Sheffield) used in the European aerospace
industry and as such is not part of the AISI series. S143/4/5 is not AMS
5659. AMS 5659 is 15/5PH grade which has less Ni and Mo but a bout 3.5% Cu.
This too has several heat treatment conditions.
Just to add about specs. The British Standard 'S' series aerospace specs are
widely recognised in the British and European aerospace industries but most
of the grades have AMS equivelents and are thus named differently by the
Just a few examples:
S155 = AMS 6417/6419/6527 - used to make aircraft undercarrages (and drive
shafts in Formula 1)
S132 = the main alloy used to make central shafts in commerial jet engines
(and Formula 1 crankshafts)
S82/156 = used in many commercial/military helicopters for gears in the main
gearbox (and some Formula 1 cars / Bugatti Veryon)
On the drawings, AMS 5659 is offered as an alternative but is heat treated
if used. Does S143 fall into the austenitic or marstenitic category?
As the material is supplied in certain diameter lengths I take it the
material would be cold drawn, but would they at any point be quenched and
tempered or annealed?
Most precipitation hardening grades are supplied in 1 of 3 conditions:
1. Softened (annealed): typically 650 deg C for up to 12hrs - for
2. Solutuion treated: 1050 deg C for 1/2 to 1hr, cooled in air or oil -
for rough machining:
2. Precipitation hardened: depends on grade but notmally between 450 and
650 deg C for 1 to 6 hrs - final heat treatment usually with some finish
machining or ginding before final use.
Unlike alloy steels, PH stainless steels are softer after solution treatment
than after precipitation hardening which is why most maching is done after
solution treatment. Normally these types of steels are not cold drawn but
turned/peeled to produce a fine finish. The company I work for makes 15,000+
tonnes of these types of steels per year and the majority of this type of
steel is supplied in the solution treated condition and bright finished.
As for 15-5PH (AMS 5659) as an alternative to S143, you need to be careHul
what finish heat treatment condition is required. 15-5Ph has 5 or 6
different precipitation hardening treatments depending on the required
combination of tensile strength and toughness. The conditions are H900,
H925, H975, H1025, H1075 & H1150, the number refering to the final heat
treatment temperature in deg Fahrenheit. The higher the temperature the more
toughness is sachived but at the expense of tensile strength. Typicall
15-5PH is used in the H1025 condition which gives the best combination of