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BS 3146: (1975) PART 2: ANC
1
Description
13% chromium ferritic-martensitic steel
casting. Apart from the very low carbon-content alloys, these steels are capable
of being heat-treated by conventional low alloy practice to give a wide spread
of mechanical properties ranging from hardness levels of 150 – 500 Brinell.
Depending on the particular composition and heat treatment applied, they can
be used in a variety of applications where corrosion resistance is required
at normal and elevated temperatures, along with reasonable strength, ductility
and impact resistance and, at the high carbon levels, good wear resistance.
Typical uses range from steam generation equipment to surgical implements.
Additional Information
- Weldability is not considered to be
good but where necessary pre-heat and post-weld treatment should be applied.
Oxyacetylene gas welding is liable to cause carbon pick-up therefore metal
arc or inert gas methods are preferable.
- Machinability –
These alloys can be readily softened by conventional annealing practice and
machinability is generally good and free-cutting grades are available.
- Corrosion resistance
– These alloys are virtually rustproof, with good resistance to attack by
many organic mediums and environments of an oxidizing nature in relatively
mild service.
BS 3146: (1975) PART 2: ANC
2
Description
18% chromium 2% nickel martensitic steel
castings. A relatively high tensile stainless steel for general engineering
purposes combining improved corrosion resistance over the 13% chromium grades
with a strength level of 850N/mm². Typical applications include pump and valve
parts in engineering and aircraft service where corrosive conditions do not
require an austenitic stainless but where the higher strength is necessary.
Additional Information
- Weldability is poor
and welding is not generally recommended
- Machinability is
good although tipped tools are necessary to combat the abrasives carbide.
BS 3146: (1975) PART 2: ANC
3
Description
18% chromium 8% nickel austenitic corrosion
resistant steel castings for general engineering purposes. The two grades combine
moderate strength with excellent resistance to atmospheric and oxidizing media
attack along with very good low temperature stability, particularly in the case
of Grade A, and reasonable hot strength. Their wide range of applications include
the chemical, pharmaceutical, textile,
food- processing and dairy industries.
Additional Information
- Weldability is good
although argon arc is preferred to gas methods, in the latter case fluxes
are necessary and there is a danger of carbon pick-up.
- Machinability is
only fair as the alloys are relatively soft and work harden rapidly as a result
of using blunt tools, low feeds and interrupted cuts. For this reason high
feeds, low speeds and tipped tools are recommended, although for really good
machinability a free-cutting grade should be used.
Other Comments
- Corrosion resistance
– These alloys have excellent resistance to general corrosive attack and specifically
to strongly oxidizing media including boiled nitric and sulphuric acid, sulphates
and organic acids. The unstabilised grade is liable to suffer severe intergranular
attack if used under conditions which cause carbide precipitation or if not
solution treated after welding.
- Sub-zero Properties
– These alloys have very good stability at sub-zero temperatures particularly
with the unstabilised grade and can be used at temperatures down to -225°C.
For optimum properties the carbon and stabilising additions should be kept
at a very low level.
BS 3146: (1975) PART 2: ANC
4
Description
Austenitic chromium-nickel-molybdenum,
corrosion resistant steel castings for general engineering purposes. General
properties are similar to the 18/8 stainless steel but the addition of molybdenum
improves corrosion resistance to reducing media and reduces pitting by chlorides
as in sea water. Typical applications include textile, paper and chemical industries
and a wide range of marine fittings.
Additional Information
- Weldability is good
although inert gas-shielded arc methods are preferred to gas, where fluxes
are necessary and there is a danger of carbon pick-up. Within the specified
compositional range the alloys can be either fully austenitic and non-magnetic
or partially magnetic depending on the amount of delta ferrite present. If
acceptable a minimum of 5% delta ferrite is generally recommended for optimum
welding characteristics.
- Machinability is
only fair as the alloys are relatively soft and work harden rapidly as a result
of using blunt tools, low feeds and interrupted cuts. For this reason high
feeds, low speeds and tipped tools are recommended, although for really good
machinability a free cutting grade should be used.
Other Comments
- Corrosion resistance
the addition of molybdenum as compared to the straight 18/8 stainless confers
improved corrosion resistance to reducing media, sulphite liquors and chloride
which tend to cause pitting as in sea water. Grade A, with the highest molybdenum,
nickel and chromium levels has the best properties in this respect, although
none of the grades are as resistant to boiling nitric acid as an 18/8 type.
Grade C has better resistance to intergranular corrosion from salt solutions
and acids at elevated temperatures.
- Sub-zero Properties
as with the 18/8 stainless these austenitic steels have good stability of
properties at sub-zero temperatures, although again the carbon and stabilising
element levels should be kept to a minimum for the best results. However,
within the ranges of composition specified it is possible for varying amounts
of delta ferrite to be present in the steels and as the level of delta ferrite
increases the notch toughness at low temperatures is reduced.
BS 3146: (1975) PART 2: ANC
5
Description
Nickel-chromium alloy steel castings
resistant to scaling at elevated temperatures. The alloys have good hot strength,
hot gas corrosion and carbon penetration resistance and improved resistance
to cyclic heating and thermal shock with increasing nickel content. Typical
applications cover a wide range of furnace and heat treatment equipment parts
where service conditions combine elevated temperatures with corrosive environments.
The alloys also have fairly good abrasion resistance, particularly with the
high carbon levels.
Additional Information
- Weldability good
– gas or electric arc methods are suitable without the necessity for post
weld treatment.
- Machinability as
with other austenitic alloys is only fair, so that it is advisable to use
high feeds, low speeds and carbide tipped tools.
Other comments
- Corrosion resistance
– resistance to corrosion by hot gases is good for all three grades. Grade
A has good resistance to attack by all heat treatment salts whereas Grades
B and C are not so resistant to neutral salts. Grade C has excellent corrosion
resistance to salts inn tempering and cyaniding baths. Grades B and C are
resistant to molten tin up to 340°C and Grade C to molten lead and vanadium
pentoxide.
- Elevated Temperature Properties
- All grades have good resistance to scaling up to 1050°C, the higher
nickel alloys being best in this respect. Maximum service temperatures are
1100° C for Grade A, 1120° for Grade B and 1150° for Grade C. All the alloys
have good resistance to carbon penetration in carburising atmosphere, good
resistance to cyclic heating, useful creep strength up to 650°C and in the
case of Grade C, excellent resistance to thermal shock.
BS 3146: (1975) PART 2: ANC
6
Description
Chromium-nickel alloy steel castings
possessing good corrosion and heat resisting properties. The alloys have good
hot strength and oxidation resistance and useful creep resistance up to 650°C.
Applications include oil refinery, heat treatment equipment, furnace and burner
parts as well as welding fixtures.
Additional Information
- Weldability is good,
gas or electric arc methods being suitable without the necessity for post-weld
treatment. However, it is recommended that castings should be stabilised prior
to welding at not less than 950°C.
- Machinability as
with other austenitic alloys, is only fair, so that it is advisable to use
high feeds, low speeds and tipped tools.
Other Comments
- Corrosion resistance
the alloys are not designed specifically for resistance to corrosion but rather
for heat resistance. In comparable corrosive conditions it is probable that
lower alloy content austenitic stainless steels would be adequate at lower
temperatures and the high alloy ANC 5 type materials more suitable at higher
temperatures.
BS 3146: (1975) PART 2: ANC
8
Description
A readily weldable heat resistant alloy
combining excellent resistance to oxidation at temperatures up to 1100°C with
useful strength at high temperatures.
Additional Information
- Weldability this
alloy is readily weldable using argon arc resistance welding.
- Machinability –
tungsten carbide tipped tools are recommended. Avoid work hardening by maintaining
a good cutting action.
BS 3146: (1975) PART 2: ANC
9
Description
A heat resistant alloy which can be used
“as-cast” but which develops optimum properties in the solution treated and
aged condition, resists oxidation up to at least 1050°C and retains high creep
resistance up to approximately 850°C.
Additional Information
- Weldability – The
alloy is not readily weldable.
- Machinability –
Can be machined with correct tooling and practice.
BS 3146: (1975) PART 2: ANC
10
Description
A heat resistant alloys which can be
used “as-cast” but which develops optimum properties in the finally heat treated
condition. Resists oxidation to 1050°C and creep resistance is maintained to
900°C.
Additional Information
- Weldability – the
alloy is not readily weldable.
- Machinability – machinable
with correct tooling and practice.
BS 3146: (1975) PART 2: ANC
11
Description
An intermediate strength alloy particularly
resistant to oxidation and thermal fatigue at temperatures above 1000°C with
good thermal shock resistance up to 1100°C.
Additional Information
- Weldability – not
readily weldable
- Machinability –
can be machined with correct tooling and practice
BS 3146: (1975) PART 2: ANC
13
Description
A heat resistant machinable alloy with
high strength and resistance to oxidation at both room and elevated temperatures.
Corrosion resistance is of the same order as for austenitic stainless steel.
Resistance to galling and wear. Useful creep strength and thermal shock properties.
Additional Information
- Weldability – This
material can be welded using the tungsten inert gas method with a pre-heat
of approximately 250° C if possible. After welding ensure that it is cooled
slowly away from draughts.
- Machinabiliy – Tungsten
carbide tipped tools at cutting speeds of 20-50 ft per min. Threads can be
single point turned but tapping is not possible.
Guide Holes <3/32” diameter spark
erosion
> 3/32” carbide
tipped tools
BS 3146: (1975) PART 2: ANC
14
Description
A heat resistant machinable alloy of
high strength with good oxidation resistance at room and elevated temperatures.
Corrosion resistance is of the same order as for the austenitic stainless steels,
good low temperature impact properties and resistant to galling and water.
Additional Information
- Weldability – this
material can be welded using the tungsten inert gas method with a pre-heat
of approximately 250°C if possible. After welding ensure that it is cooled
slowly away from draughts.
- Machinability –
tungsten carbide tipped tools at cutting speed of 20-50 ft per min. Threads
can be single point turned but tapping is not possible.
Guide Holes <3/32” diameter spark
erosion
> 3/32” carbide
tipped tools
BS 3146: (1975) PART 2: ANC
15
Description
A corrosion and heat resistant alloy
with good resistance to acids under arduous conditions. Useful creep strengths
up to 800°C. Used in chemical, petroleum and pickling plant equipment.
Additional Information
- Weldability – all
commonly used welding methods may be used, however, oxyacetylene welding is
not recommended when components are to be used in corrosive environments.
- Machinability –
readily machinable.
BS 3146: (1975) PART 2: ANC
16
Description
A heat resistant alloy with good corrosion
resistance, particularly with regards to oxidizing acids at high temperatures.
Used in chemical plant.
Additional Information
- Weldability – Weldable
by any process other than oxyacetylene welding.
- Machinability –
readily machinable.
BS 3146: (1975) PART 2: ANC
17
Description
A corrosion resistant alloy, particularly
against sulphuric acid in high concentration and at temperatures near boiling
point. Avery hard alloy with limited tensile ductility. Used in chemical plant.
Additional Information
- Weldability – Can
be weldable by any welding process.
- Machinability – readily
machinable.
BS 3146: (1975) PART 2: ANC
18
Description
Good corrosion resistant alloys with
increased electrical and thermal conductivity. Used for marine fittings and
general engineering applications where resistance to corrosion is of prime importance.
Additional Information
- Weldability – easily
brazed and resistance welded.
- Machinability –
machinable in the “as-cast” condition.
BS 3146: (1975) PART 2: ANC
19
Description
Nickel alloy for use in moderately stressed
components up to 870°C. Used for turbo charger discs, gas turbine components
and diesel engine pre-combustion chambers.
Additional Information
- Weldability – can
be welded with care and correct choice of conditions and filler alloy.
- Machinability –
machinable with the correct tooling and practice.
Other comments
This alloy may be used “as-cast” but
develops optimum properties in the fully
heat- treated condition. Properties deteriorate
with increase in nitrogen. Use of scrap for remelting must be carefully controlled.
BS 3146: (1975) PART 2: ANC
20
Description
Heat-treatable corrosion resistant steel.
Used for steam and gas turbine applications, high-duty rotating parts which
can operate at fairly high temperatures. Used for chemical plant components,
compressors and internal combustion engine exhaust valves.
Additional Information
Other comments
Impact and elongation properties are
improved by maintaining the silicon and niobium contents at a minimum.
BS 3146: (1975) PART 2: ANC
21
Description
Ferritic – austenitic stainless steel
combining good mechanical properties with excellent resistance to corrosion
and erosion. Used mainly in the chemical field for resistance to most acids
and also usefully for marine use where medium strength is important.
Additional Information
- Weldability – TIG
welding is required using a stabilized stainless welding rod.
Other comments
Magnetic permeability is approximately
3.5.
BS 3146: (1975) PART 2: ANC
22 – 17/4 PH
Description
A precipitation hardening stainless steel.
Additional Information
- Weldability is similar
to 18/8 stainless steels.
- Machinability – This
alloy is readily machinable in the annealed and tempered condition and is
capable of developing a particularly fine finish. Simple machining such as
turning can be carried out in the fully hardened condition.
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