ASTM A240 S31254 254SMO Stainless Steel Flat Sheet High Tensile Strength

Product Details:
Place of Origin: China
Brand Name: VANFORGE
Certification: ISO9001, ISO10012, ISO14001, OHSAS18001, ABS, BV, DNV, Lloyd, NK, PED
Payment & Shipping Terms:
Minimum Order Quantity: 1000 kg
Price: Negotiable
Packaging Details: Seaworthy package for export
Delivery Time: 45 days
Payment Terms: L/C, T/T
Supply Ability: 100 tons per month

Detail Information

Material: Austenitic Stainless Steels, Duplex Stainless Steels Process: Cold Rolled
Treatment: Bright Annealed Surface: BA Or On Request
Application: Petrochemical, Chemical, Paper And Pulp Feature: High Precision
Standard: ANSI, ASTM, ASME, EN, DIN, JIS, GOST
High Light:

stainless steel plate

,

polished stainless steel sheet

Product Description

ASTM A240 S31254 254SMO cold rolled stainless steel flat sheet

 

UNS S31254 Sheet

 

UNS S31254 is a high-alloy austenitic stainless steel developed for use in seawater and other aggressive chloride-bearing media. The steel is characterized by the following properties:

  • Excellent resistance to pitting and crevice corrosion
  • High resistance to general corrosion
  • High resistance to stress corrosion cracking
  • Higher strength than conventional austenitic stainless steels
  • Good weldability

 

Standards

  • UNS S31254
  • EN number 1.4547
  • EN name X1CrNiMoCuN20-18-7
  • W.Nr. 1.4529**
  • SS 2378*
  • AFNOR Z1 CNDU 20.18.06AZ*

* Obsolete. Replaced by EN.
** Nearest equivalent grade.

 

Product standards

  • Seamless tube and pipe: ASTM A269, A213, A312, NFA 49-217, EN 10216-5
  • Welded tube and pipe: ASTM A249, A269 , A312, A358, A409
  • Fittings: ASTM A182
  • Bar: ASTM A276, A479, EN 10088-3
  • Forged products: ASTM A473
  • Sheet and plates: ASTM A240

 

Approvals

  • UNS S31254 (254 SMO) in the form of seamless pipe has been approved by the American Society of Mechanical Engineers (ASME) for use according to ASME Boiler and Pressure Vessel Code section VIII, div. 1. However, there is no approval for UNS S31254 in the form of seamless tube, but according to the ASME paragraph UG-15 it is allowed to use the design values for seamless pipe according to ASME section VIII, div. 1 also for seamless tube.
  • NACE MR 0175 (sulphide stress cracking resistant material for oil field equipment)

Chemical composition (nominal) %

C

Si

Mn

P

S

Cr

Ni

Mo

N

Cu

max.

max.

max.

max.

max.

         
0.020 0.80 1.00 0.030 0.010 20 18 6.1 0.20 0.7

 

Mechanical properties

The following figures apply to solution annealed condition seamless tube and pipe.

At 20°C (68°F)

Metric units

Thickness

Proof strength

Tensile strength

Elong.

Hardness

 

Rp0.2a

Rp1.0a

Rm

Ab

A2"

HRB

mm

MPa

MPa

MPa

%

%

 
 

min.

min.

 

min.

min.

max.

<5 310 340 675-850 35 35 96
>5 310 340 655-850 35 35 96

 

Imperial units
Thickness Proof strength Tensile strength Elong. Hardness
  Rp0.2a Rp1.0a Rm Ab A2" HRB
mm MPa MPa MPa % %  
  min. min.   min. min. max.
<0.187 45 49 98-123 35 35 96
>0.187 45 49 98-123 35 35 96

1 MPa = 1 N/mm2
a) Rp0.2 and Rp1.0 correspond to 0.2% offset and 1.0% offset yield strength, respectively.
b) Based on L0 = 5.65 √S0 where L0 is the original gauge length and S0the original cross-section area.

 

Impact strength

Due to its austenitic microstructure, UNS S31254 has very good impact strength both at room temperature and at cryogenic temperatures.

 

Tests have demonstrated that the steel fulfils the requirements (60 J (44 ft-lb) at -196 oC (-320 oF)) according to the European standards EN 13445-2 (UFPV-2) and EN 10216-5.

 

At high temperatures

Intermetallic phases are precipitated within the temperature range of 600–1000°C (1110–1830°F). Therefore, the steel should not be exposed to these temperatures for prolonged periods.

 

Metric units
Temperature Proof strength
°C Rp0.2 Rp1.0
  MPa MPa
  min. min.
100 230 270
200 190 225
300 170 200
400 160 190
500 148 180

 

Imperial units

Temperature

Proof strength

°F

Rp0.2

Rp1.0

 

ksi

ksi

 

min.

min.

200 34 40
400 27 32
600 24 29
700 24 28
900 22 26

 

ASTM A240 S31254 254SMO Stainless Steel Flat Sheet High Tensile Strength 0

Figure 1. Strength values (min. values) for UNS S31254 and allowable stress according to ASME Boiler and Pressure Vessel Code section VIII, div. 1.

 

Physical properties

Density: 8.0 g/cm3, 0.29 lb/in3

 

Thermal conductivity

Temperature, oC

W/m oC

Temperature, oF

Btu/ft h oF

20 10 68 6
100 12 200 7
200 14 400 8
300 16 600 9.5
400 18 800 10.5
500 20 1000 11.5
600 21 1200 12.5
700 23 1300 13

 

Specific heat capacity
Temperature, °C J/kg °C Temperature, °F Btu/ft h °F
20 485 68 0.12
100 510 200 0.12
200 535 400 0.13
300 565 600 0.14
400 585 800 0.14
500 600 1000 0.14
600 615 1200 0.15
700 625 1400 0.15

 

Thermal expansion, mean values in temperature ranges (x106)

Temperature, °C

Per °C

Temperature, °F

Per °F

30–100 16 86–200 9
30–200 16 86–400 9
30–300 16.5 86–600 9
30–400 16.5 86–800 9.5
30–500 17 86–1000 9.5
30–600 17 86–1200 9.5
30–700 17.5 86–1300 10

 

Modulus of elasticity, (x103)
Temperature, °C MPa Temperature, °F ksi
20 195 68 28.3
100 190 200 27.6
200 182 400 27.5
300 174 600 25.1
400 166 800 23.8
500 158 1000 22.5

 

Corrosion resistance

In solutions containing halides such as chloride and bromide ions, conventional stainless steels can be readily attacked by local corrosion in the form of pitting corrosion, crevice corrosion or stress corrosion cracking (SCC). In acid environments, the presence of halides also accelerates general corrosion.

 

General corrosion

In pure sulphuric acid, UNS S31254 is much more resistant than ASTM TP316, and in naturally aerated sulphuric acid containing chloride ions UNS S31254 exhibits higher resistance than '904L', see Figure 2.

 

ASTM A240 S31254 254SMO Stainless Steel Flat Sheet High Tensile Strength 1

Figure 2. Isocorosion diagram 0.1 mm/year (4mpy) in naturally aerated sulphuric acid containing 2000 ppm chloride ions.

 

Stress corrosion cracking (SCC)

Ordinary austenitic steels of the ASTM TP304 and TP316 type are prone to stress corrosion cracking (SCC) in chloride-containing solutions at temperatures exceeding about 60°C (140°F). For the austenitic steels, resistance to SCC increases with higher nickel and molybdenum contents. The tables below show the results of two accelerated tests, clearly demonstrating that UNS S31254 has a very good resistance to SCC.

 

Stress corosion cracking tests in boiling 25% NaCl solution, pH=1.5. U-bend specimens.

Grade

Time to failure

Remark

ASTM TP316 <150 h Pitting
'904L' No failure (1000 h) Crevice corrosion
UNS S31254 No failure (1000 h) No attack

 

Stress corrosion cracking tests. Drop evaporation method*. Stress: 0.9xRp0.2

Grade

Time to failure hours

ASTM TP316 105
'904L' 225
UNS S31254 425

* A 0.1 M NaCl solution is allowed to drop slowly onto an electrically heated
tensile test specimen at 300 oC (570 oF).

 

Intergranular corrosion

UNS S31254 has a very low carbon content. This means that there is very little risk of carbide precipitation during heating, for example when welding. The steel passes the Strauss test (ASTM A262, practice E) even after sensitizing for one hour at 600–1000°C (1110–1830°F).

However, due to the high alloying content of the steel, inter-metallic phases can precipitate at the grain boundaries in the temperature range 600–1000°C (1110–1830°F). These precipitations do not involve any risk of intergranular corrosion in the environments in which the steel is intended to be used. Thus, welding can be carried out without any risk of intergranular corrosion.

 

Pitting corrosion

Its high chromium content and particularly the molybdenum content give UNS S31254 excellent resistance to pitting and crevice corrosion. The high nitrogen content also improves pitting resistance.

The results of laboratory determination of the critical pitting temperature (CPT) in 3 % NaCl are shown in Figure 3, where it can be seen that UNS S31254 possesses very good resistance in water containing chlorides. UNS S31254 is, therefore, a suitable material for use in seawater.

 

Crevice corrosion

The weak point of conventional stainless steels is their limited resistance to crevice corrosion. In seawater, for example, there is a considerably greater risk of crevice corrosion under gaskets, deposits or fouling. Tests in natural seawater at 60°C (140°F) have shown that UNS S31254 can be exposed for prolonged periods without suffering crevice corrosion. Figure 4 shows the results of accelerated crevice corrosion tests.

 

ASTM A240 S31254 254SMO Stainless Steel Flat Sheet High Tensile Strength 2

Figure 3. Critical pitting temperature (CPT) in 3% NaCl, 600 mV/SCE.

 

ASTM A240 S31254 254SMO Stainless Steel Flat Sheet High Tensile Strength 3

Figure 4. Critical crevice corrosion temperature in FeCl₃ for UNS S31254, AISI 316L and 904L. According to ASTM G-48.

 

Heat treatment

The tubes are delivered in heat treated condition. If additional heat treatment is needed due to further processing the following is recommended.

 

Solution annealing

1150–1200°C (2100–2190°F), quenching in water. Thin-walled tubes min. 1130°C (2060°F), quenching in air/water.

 

Welding

The weldability of UNS S31254 is good. Welding should be undertaken without preheating, and if correctly performed there will be no need for any subsequent heat treatment. Suitable methods of fusion welding are manual metal-arc welding with covered electrodes and gas-shielded arc welding, mainly by means of the TIG and MIG methods.

 

Since the material is intended for use under severe corrosive conditions, welding must be carried out with care and followed by thorough cleaning to ensure that the weld metal and the heat-affected zone maintain the best possible corrosion properties.

The heat input during welding should not exceed 1.5 kJ/mm, and in multi-pass welding the interpass temperature should not exceed 100°C (210°F). A stringer bead welding technique should be used.

 

The welding of fully austenitic steels usually entails a risk of hot-cracking in the weld metal, particularly if the weldment is under constraint. However, since UNS S31254 has a very high degree of purity, the risk of this type of cracking is greatly reduced. Backing bars or similar devices of copper alloys must not be used since copper penetration into the grain boundaries in stainless steel can lead to cracking.

In common with all austenitic stainless steels, UNS S31254 has low thermal conductivity and high thermal expansion. For this reason, welding should be carefully planned in advance so that distortion of the welded joint can be minimized. If, despite these precautions, it is believed that residual stresses may impair the function of the weldment, it is recommended that the entire structure be solution annealed. See under Heat treatment.

 

In the as-supplied condition, the material has a homogeneous structure. Welding without filler metal leads to structural changes that reduce corrosion resistance. Such welding should be followed by solution annealing in order to ensure that the corrosion properties of the weld metal are equal to those of the parent metal.

 

Fabrication

Avoid abrasion against copper/copper alloys or other similar metals which, if present in metallic form, can cause cracks during subsequent welding, hot processing or heat treatment.

 

Bending

The excellent formability of UNS S31254 permits cold bending to very tight bending radii. Annealing is not normally necessary after cold bending.

 

Applications

UNS S31254 is used in the following applications:

  • Equipment for handling of seawater, such as, seawater cooling, cooling water pipes, ballast water systems, firefighting systems etc.
  • Hydraulic and instrumention tubing
  • Equipment in pulp bleaching plants
  • Components in gas cleaning systems
  • Tanks and pipelines for chemicals with high halide contents

Production process

ASTM A240 S31254 254SMO Stainless Steel Flat Sheet High Tensile Strength 4

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