Duplex stainless steel: 1.4410 - S32750 - Alloy 2507 - X2 CrNiMoN 25-7-4

Super Duplex UNS S32750 is the most common super duplex grade in the market.

UNS S32750 is a duplex stainless steel especially designed for service in aggressive chloride-containing environments. It has very good resistance to localized corrosion and stress corrosion cracking in combination with high mechanical strength. It is widely used in oil & gas, hydropower, pressure vessels, pulp & paper, structural components and chemical tankers.

APPLICATIONS

The main applications are for details with special requirements for high corrosion resistance.

UNS S32750 is characterized by:

• High resistance to stress corrosion cracking in halide containing environments.

• High resistance to pitting and crevice corrosion.

• High resistance to general corrosion.

• High mechanical strength.

• High resistance to erosion corrosion and corrosion fatigue.

 

Mechanical Properties

Tensile strength:	750	N/mm²
Yield strength 0,2% :	550	≥ N/mm²
Elongation:	25	≥ %
Hardness HB30:	270	≤ HB

Chemical Composition

Carbon C 0,03% max

Silicon Si 0,80% max

Magnese Mn 1,20% max

Phosphorus P 0,035% max

Sulphur S 0,020% max

Chromium Cr 24-26% max

Nickel Ni 6-8% max

Nitrogen N 0,24-0,32% max

Heat Treatment

Solution annealing at 1100°C followed by water quenching

Corrosion Testing

 High resistance to stress corrosion cracking in halide containing environments.
• High resistance to pitting and crevice corrosion.
• High resistance to general corrosion.
• High mechanical strength.
• High resistance to erosion corrosion and corrosion fatigue.

Welding

Very good

Source: 

https://www.gemaco-piping.com/materials/duplex-superduplex/1-4410-uns-s32750-alloy-2507-x2-crnimon-25-7-4/

https://www.sverdrupsteel.com/products/alloy-1-4410-super-duplex-uns-s32750-f53-2507

316L Grade UREA for urea plant applications: Properties, Chemical Composition

1.4435; X2CrNiMo18-14-3; 316L G.Urea; S31603

The UREA 316L grade has been specially developed for urea plant applications. It is a 316L modified stainless steel with extra – low silicon content and substantial higher molybdenum contents. The low carbon content, combined with a well balanced chemistry (low silicon and nickel content close to 14%) makes the alloy fully austenitic, free of intermetallic phase precipitations. The ferrite level is kept under 0.5% in the solution annealing and water quenched conditions. The UREA 316L grade is designed for the fabrication of lining interiors in urea units for improved corrosion resistance properties in urea – carbonate environments or complementary products (pipes, fittings…). The alloy is not designed for nitric acid application.

316L UG pipes

Mechanical Properties

Tensile strength:	500-700	N/mm²
Yield strength 0,2% :	200	≥ N/mm²
Elongation:	40/30	≥ %
Hardness HB30:	215	≤ HB

Chemical Composition

Carbon C 0,020% max

 Silicon Si 0,40% max

 Magnese Mn 2% max

 Phosphorus P 0,045% max

 Sulphur S 0.015% max

 Chromium Cr 17,0-19,0 min

 Molybdenum Mo 2,2-3%

 Nickel Ni 12,5-15,0%

Heat Treatment

at 1120 – 1180°C (2048 – 2156°F) followed by water quenching.

Corrosion Testing

 Typical maximum corrosion results required following different specifications after Huey tests (ASTM A262 C – five periods of 48 h.) are:

• maximum weight loss lower than 3,3 μm/48 h (130 mg/dm² per 24 h.)
• maximum depth for microcracks of 200 μm in the long direction and 70 μm in the transverse direction.

Nondestructive testing

•  Ferrite check 100% (less than 0,5%)
• Measurement location chosen by Inspector.

Welding

 Welding The UREA 316L grade can be welded with most of the welding processes: TIG, Plasma, MIG welding, as well as SMAW, SAW or FCAW processes. The alloy is sensitive to hot cracking phenomenon due to its fully austenitic microstructure. Weld should be performed in order to obtain extra – low ferrite contents, no carbide or nitrides precipitations, low silicon contents as well as no intermetallic phases precipitations. Higher manganese content products should be considered.

Source: https://www.gemaco-piping.com/materials/urea-grades/1-4435-x2crnimo18-14-3-316l-s31603/

UREA 25.22.2 -310MoLN – UNS S31050

UREA 25.22.2 chemical composition has been optimized for specific uses in Urea plants. 

It is a 310L modified austenitic stainless steel with low carbon, low silicon and high nitrogen additions in order to stabilize and strengthen the austenitic phase. The alloy is particularly designed for improved corrosion resistance properties in 

Ammonium carbamate environments including strippers. The grade is also well designed for resistance in wet corrosive conditions due to its high contents of chromium, molybdenum and nitrogen (PREN > 33). 

UREA 25.22.2 is designed for the fabrication of lining interiors in Urea units or complementary products (pipes, fittings…). The grade can be used for urea strippers.

Liner strip UREA 25.22.2 -310MoLN – UNS S31050 for relining Urea reactor in Fertilizer Plants

Mechanical Properties

Tensile strength:	540-740	N/mm²
Yield strength 0,2% :	250	≥ N/mm²
Elongation:	35/30	≥ %
Hardness Brinell:	240	≤ HB

Chemical Composition

Carbon C 0,020% max

Silicon Si 0,40% max

Manganese Mn 2% max

Phosphorus P 0,020%max

Sulphur S 0,010% max

Chromium Cr 24-26%

Molybdenum Mo 2,0-2,6%

Nickel Ni 21-23,5%

Nitrogen N 0,10-0,15%

Heat Treatment

heat treatment (1140°-1180°C –2084-2156°F) and water quenching

Corrosion testing

The corrosion resistance properties are enhanced thanks to the low carbon level, low silicon level and complementary additions of nitrogen.

Typical maximum corrosion results required following different specifications for the 25.22.2 grade after 5 periods of 48 h following ASTM A 262-C practice are:

maximum general corrosion: 1,6 μm/48 h or 65 mg/dm² per hour with a maximum depth of microcracks of 100 μm in the long direction of rolling.

Non destructive testing

• Ferrite check 100% (less than 0,5%)
• Measurement location chosen by Inspector

Welding

UREA 25.22.2 can be welded with most of the welding processes : TIG, Plasma, MIG welding, as well as SMAW, SAW or FCAW processes. The alloy is sensitive to hot cracking phenomenon due to its fully austenitic microstructure. Weld should be performed in order to obtain extra-low ferrite contents, no carbide or nitride precipitations, low silicon contents as well as no intermetallic phase precipitations. Higher manganese content products should be considered.

Source: https://www.gemaco-piping.com/materials/urea-grades/1-4466-urea-25-22-2-310moln-uns-s31050/

Properties of Mould Stainless Steel SCS13

Chemical composition % 

C ≤	Si ≤	Mn ≤	P ≤	S ≤	Cr	Ni
0.08	2.0	2.0	0.04	0.04	18-21(23)	8-11

Properties of grade SCS13

Annealing hardness HBS	Cold pull hardness HBS	Preheating temperature ℃	Quenching temperature ℃		Holding time min	Hardening medium	Temper temperature ℃	After tempering hardness ≥HRC
			salt-bath furnace	controlled atmosphere furnace
235	262	788	1191	1204	5～15	air cooling	522	60

Steel plate/Sheet thickness / mm	σb MPa	σs ≥/MPa	δ Samples from the standard for 50 mm (2 in)	180 ° of cold bending test
				longitudinal	horizontal
Hot-rolled/Cold rolling:5 - 150	520	415	16～18	2a	3.5a

Super Duplex UNS S32750: Composition and Properties

Super Duplex UNS S32750 Data Sheet

UNS S32750 Super Duplex, also know by its trade name SAF2507 has a microstructure 50% austenite and 50% ferrite.  The material exhibits high mechanical strength with outstanding corrosion resistance in marine environments.  32760 typically as a min PREN of 40.  Due to these features the material is regularly used in place of the 300 stainless series, 22% Cr Duplex and precipitation hardening grades such as 17-4PH.

 Common Applications of UNS S32750

Seawater Filter

Waste water/Desalination

Chemical Plants

Oil & Gas

  UNS S32750 Chemical Composition

C (Carbon)                      0.03%  Max

Cr (Chromium)               24.0-26.0%

Fe (Iron)                           Balance

Mn (Manganese)             2.0% Max

Mo (Molybdenum)          3.0-4.5%

Ni (Nickel)                        6.0-8.0%

N (Nitrogen)                     0.24-0.35%

P (Phosporous)                0.035% Max

Si (Silicon)                        1.0% Max

S (Sulphur)                      0.015% Max

  UNS S32750 Physical Properties

 Density            7800kg/m3

  UNS S32750 Mechanical Properties

 Hardness  Brinell                           290 Max

Tensile Strength @ Break               930Mpa  / 135000psi        

Tensile Strength @ Yield                530Mpa / 77000 psi    0.2% offset

Elongation @ Yield                        25%

Modulus of Elasticity                      200Gpa          29000 ksi

*Above properties typical values at room temp

  UNS S32750 Thermal Properties

 CTE Linear                       13.0mm/m-ºC (@temp 100ºC)

                                           13.5mm/m-ºC (@temp 200ºC)

                                            14.0mm/m-ºC (@temp 300ºC)

                                             14.5mm/m-ºC (@temp 400ºC)

Specific Heat Capacity     0.500J/g-ºC                             20ºC

*Please consider the Environment before printing

Properties of Stainless steel AISI 310

AISI Type 310 is an Austenitic Standard grade Stainless Steel. It is commonly called AISI Type 310 Chromium-Nickel steel.Composition
Element  Weight %
C         0.25
Mn      2.00
Si        1.50
Cr       24.0-26.0
Ni       19.0-22.0
P        0.045
S        0.03


Equivalent grades:

 France: AFNOR Z 12 CNS 25.20
 Germany: DIN 1.4841
 Italy: UNI X 16 CrNiSi 25 20 , UNI X 22 CrNi 25 20
 Japan: JIS SUS Y 31O
 United Kingdom: B.S. 310 S 24
 United States: AMS 5694 , AMS 5695 , ASME SA182 , ASME SA213 , ASME SA249 , ASME SA312 , ASME SA358 , ASME SA403 , ASME SA409 , ASTM A167 , ASTM A182 , ASTM A213 , ASTM A249 , ASTM A276 , ASTM A312 , ASTM A314 , ASTM A358 , ASTM A403 , ASTM A409 , ASTM A473 , ASTM A511 , ASTM A580 , ASTM A632 , FED QQ-S-763 , FED QQ-S-766 , FED QQ-W-423 , FED STD-66 , MIL SPEC MIL-S-862 , SAE 30310 , SAE J405 (30310) , UNS S31000

Mechanical Properties

 Density (×1000 kg/m3)    8
 Poisson's Ratio                0.27-0.30
 Elastic Modulus (GPa)    200
 Tensile Strength (Mpa)    515
 Yield Strength (Mpa)      205
 Elongation (%)               40
 Reduction in Area (%)    50
 Hardness (HRB)            95 (max)


Thermal Properties
 Thermal Expansion (10-6/ºC)   15.9
 Thermal Conductivity (W/m-K) 14.2
 Specific Heat (J/kg-K)              500

Electric Resistivity (10-9W-m)  780

Properties of Stainless Steel - Grade 316, 316L

SX 316 / 316L Technical Data

 Summary

SX 316 is an improved version of SX 304, with the addition of molybdenum and a slightly higher nickel content. The resultant composition of SX 316 gives the steel much increased corrosion resistance in many aggressive environments.  The molybdenum makes the steel more resistant to pitting and crevice corrosion in chloride-contaminated media, sea water and acetic acid vapours.   The lower rate of general corrosion in mildly corrosive environments gives the steel good atmospheric corrosion resistance in polluted marine atmospheres.
SX 316 offers higher strength and better creep resistance at higher temperatures than SX 304.  SX 316 also possesses excellent mechanical and corrosion properties at sub-zero temperatures.  When there is a danger of corrosion in the heat-affected zones of weldments, the low-carbon variety SX 316L should be used.  SX 316 Ti, the titanium-stabilised version, is used for its resistance to sensitization during prolonged exposure in the 550^oC-800^oC temperature range.

 

Typical Applications

Because of its superior corrosion and oxidation resistance, good mechanical properties and fabricability, SX 316 has applications in many sectors of industry.  Some of these include:
Tanks and storage vessels for corrosive liquids.
Specialised process equipment in the chemical, food, paper, mining, pharmaceutical and petroleum industries.
Architectural applications in highly corrosive environments.

Chemical Composition (ASTM A 240)
 

	C	Mn	P	S	Si	Cr	Ni	Mo	Ti
SX316 SX316L SX316Ti	0.08 max 0.03 max 0.08 max	2.0 max	0.045 max	0.030 max	1.0 max	16.0 to 18.0	10.0 to 14.0	2.00 to 3.00	- 0.5 max 5X%C

Typical properties in the annealed condition
The properties quoted in this publication are typical of mill products and unless indicated must not be regarded as guaranteed minimum values for specification purposes.

1. Mechanical properties at room temperature
 

	SX316		SX316L		SX316Ti
	Typical	Minimum	Typical	Minimum	Typical	Minimum
Tensile Strength, MPa	580	515	570	485	600	515
Proof Stress (0.2 % offset), MPa	310	205	300	170	320	205
Elongation (Percent in L = 5.65 So)	55	40	60	40	50	40
Hardness (Brinell)	165	-	165	-	165	-
Erichsen Cup Test Value mm	8 - 10	-	10 - 11	-	-	-
Endurance (fatigue) limit, MPa	260	-	260	-	260	-

2. Properties at elevated temperatures
The values given refer to SX 316 and SX 316 Ti only as strength values for SX 316L fall rapidly above 425^oC.

Short Time Elevated Temperature Tensile Strength

Temperature, C	600	700	800	900	1000
Strength, MPa	460	320	190	120	70

Creep data
Stress for a creep rate of 1% in 10 000 h

Temperature, oC	550	600	650	700	800
Stress, MPa	160	120	90	60	20

Recommended Maximum Service Temperature
(Oxidising conditions)

Continuous Service            925^oC
Intermittent Service             870^oC

3. Properties at Sub-Zero Temperatures
( SX 316 )
 

Temperature	oC	-78	-161	-196
Proof Strength (0.2% Offset)	MPa	400	460	580
Tensile Strength	MPa	820	1150	1300
Impact Strength (Charpy V-Notch)	J	180	165	155

4. Corrosion Resistance

4.1    Aqueous
         For specific conditions, consult VRN technical staff.  As a rough guide, the following examples are given
         for pure acid-water mixtures.
 

TemperatureoC	20	80
Concentration, (-% by mass)	10       20       40       60       80       100	10       20       40       60       80       100
Sulphuric Acid	0          1         2         2         1          0	2          2         2        2         2         2
Nitric Acid	0          0         0         0         0          1	0          0         0        0         1         2
Phosphoric Acid	0          0         0         0         1          2	0          0         0        0         1         2
Formic Acid	0          0         0         1         1          0	0          0         1        1         1         0

 Key:         0 = resistant    -    corrosion rate less than 100 mm/year
                 1 = partly resistant    -    corrosion rate 100 m to 1000 mm/year
                2 = non resistant    - corrosion rate more than 1000 mm/year
 

4.2    Atmospheric
          The performance of SX 316 compared with other metals in various environments is shown in the
          following table.  Corrosion rate is based on a 5 year exposure.
 

Environment	Corrosion Rate (mm/year)
	SX 316	Aluminium-3S	Mild Steel
Rural	0.0025	0.025	5.8
Marine	0.0076	0.432	34.0
Marine-Industrial	0.0051	0.686	46.2

Note:  For corrosion resistance of SX 316 relative to other types, see the section in Comparative Data.

4.3    Thermal Processing

4.3.1 Annealing. Heat from 1 010^oC to 1 120^oC and cool rapidly in air or water.  The best corrosion
          resistance is obtained when the final annealing temperature is above 1 070^oC.

4.3.2 Stress relieving.  Heat from 200 - 400^oC and air cool.

4.3.3 Hot working
          Initial forging and pressing:                                    1150  - 1200^oC
          Finishing temperature:                                            above 900^oC
          For upsetting operations, forgings
          should be finished between:                                   930 and 980^oC
          All hot working operations should be followed by annealing.

Note:  Soaking times to ensure uniformity of temperature are up to 12  times that required for the same thickness of mild steel.

Cold Working

SX 316 / 316L, being extremely tough and ductile, can be readily fabricated by cold working. Typical operations include bending, forming, deep drawing and upsetting.

Source: www.fanagalo.co.za

PRECIPITATION HARDENING STAINLESS STEELS – ALLOYS, PROPERTIES, FABRICATION PROCESSES

Background

Precipitation hardening stainless steels are chromium and nickel containing steels that provide an optimum combination of the properties of martensitic and austenitic grades. Like martensitic grades, they are known for their ability to gain high strength through heat treatment and they also have the corrosion resistance of austenitic stainless steels.

The high tensile strengths of precipitation hardening stainless steels come after a heat treatment process that leads to precipitation hardening of a martensitic or austenitic matrix. Hardening is achieved through the addition of one or more of the elements Copper, Aluminium, Titanium, Niobium, and Molybdenum.

The most well known precipitation hardening steel is 17-4 PH. The name comes from the additions 17% Chromium and 4% Nickel. It also contains 4% Copper and 0.3% Niobium. 17-4 PH is also known as stainless steels grade 630.

The advantage of precipitation hardening steels is that they can be supplied in a “solution treated” condition, which is readily machineable. After machining or another fabrication method, a single, low temperature heat treatment can be applied to increase the strength of the steel. This is known as ageing or age-hardening. As it is carried out at low temperature, the component undergoes no distortion.

Characterisation of Stainless Steels Precipitation hardening stainless steels are characterised into one of three groups based on their final microstructures after heat treatment. The three types are: martensitic (e.g. 17-4 PH), semi-austenitic (e.g. 17-7 PH) and austenitic (e.g. A-286). Martensitic Alloys Martensitic precipitation hardening stainless steels have a predominantly austenitic structure at annealing temperatures of around 1040 to 1065°C. Upon cooling to room temperature, they undergo a transformation that changes the austenite to martensite. Semi-austenitic Alloys Unlike martensitic precipitation hardening steels, annealed semi-austenitic precipitation hardening steels are soft enough to be cold worked. Semi-austenitc steels retain their austenitic structure at room temperature but will form martensite at very low temperatures. Austenitic Alloys Austenitic precipitation hardening steels retain their austenitic structure after annealing and hardening by ageing. At the annealing temperature of 1095 to 1120°C the precipitation hardening phase is soluble. It remains in solution during rapid cooling. When reheated to 650 to 760°C, precipitation occurs. This increases the hardness and strength of the material. Hardness remains lower than that for martensitic or semi-austenitic precipitation hardening steels ustenitic alloys remain nonmagnetic. Properties of Stainless Steels Strength of Stainless Steels Yield strengths for precipitation-hardening stainless steels are 515 to 1415 MPa. Tensile strengths range from 860 to 1520 MPa. Elongations are 1 to 25%. Cold working before ageing can be used to facilitate even higher strengths. Heat Treatment of Stainless Steels The key to the properties of precipitation hardening stainless steels lies in heat treatment. After solution treatment or annealing of precipitation hardening stainless steels, a single low temperature “age hardening” stage is employed to achieve the required properties. As this treatment is carried out at a low temperature, no distortion occurs and there is only superficial discolouration. During the hardening process a slight decrease in size takes place. This shrinking is approximately 0.05% for condition H900 and 0.10% for H1150. Typical mechanical properties achieved for 17-4 PH after solution treating and age hardening are given in the following table. Condition designations are given by the age hardening temperature in °F. Table 1. Mechanical property ranges after solution treating and age hardening Cond. Hardening Temp and time Hardness (Rockwell C) Tensile Strength (MPa) A Annealed 36 1100 H900 482°C, 1 hour 44 1310 H925 496°C, 4 hours 42 1170-1320 H1025 552°C, 4 hours 38 1070-1220 H1075 580°C, 4 hours 36 1000-1150 H1100 593°C, 4 hours 35 970-1120 H1150 621°C, 4 hours 33 930-1080

Typical Chemical Composition of Stainless Steels Table 2. Typical chemical composition for stainless steels alloy 17-4PH 17-4 PH C 0.07% Mn 1.00% Si 1.00% P 0.04% S 0.03% Cr 17.0% Ni 4.0% Cu 4.0% Nb+Ta 0.30% Typical Mechanical Properties of Stainless Steels Table 3. Typical mechanical properties for stainless steels alloy 17-4PH Grade 17-4PH Annealed Cond 900 Cond 1150 Tensile Strength (MPa) 1100 1310 930 Elongation A5 (%) 15 10 16 Proof Stress 0.2% (MPa) 1000 1170 724 Elongation A5 (%) 15 10 16 Typical Physical Properties of Stainless Steels Table 4. Typical physical properties for stainless steels alloy 17-4PH Property Value Density 7.75 g/cm3 Melting Point °C Modulus of Elasticity 196 GPa Electrical Resistivity 0.080x10-6 Ω.m Thermal Conductivity 18.4 W/m.K at 100°C Thermal Expansion 10.8x10-6 /K at 100°C Alloy Designations Stainless steels 17-4 PH also corresponds to a number of following standard designations and specifications. Table 5. Alternate designations for stainless steels alloy 17-4PH Euronorm UNS BS En Grade 1.4542 S17400 - - 630

Corrosion Resistance of Stainless Steels Precipitation hardening stainless steels have moderate to good corrosion resistance in a range of environments. They have a better combination of strength and corrosion resistance than when compared with the heat treatable 400 series martensitic alloys. Corrosion resistance is similar to that found in grade 304 stainless steels. In warm chloride environments, 17-4 PH is susceptible to pitting and crevice corrosion. When aged at 550°C or higher, 17-4 PH is highly resistant to stress corrosion cracking. Better stress corrosion cracking resistance comes with higher ageing temperatures. Corrosion resistance is low in the solution treated (annealed) condition and it should not be used before heat treatment. Heat Resistance of Stainless Steels 17-4 PH has good oxidation resistance. In order to avoid reduction in mechanical properties, it should not be used over its precipitation hardening temperature. Prolonged exposure to 370-480°C should be avoided if ambient temperature toughness is critical. Fabrication of Stainless Steels Fabrication of all stainless steels  should be done only with tools dedicated to stainless steel materials or tooling and work surfaces must be thoroughly cleaned before use. These precautions are necessary to avoid cross contamination of stainless steels by easily corroded metals that may discolour the surface of the fabricated product. Cold Working of Stainless Steels Cold forming such as rolling, bending and hydroforming can be performed on 17-4PH but only in the fully annealed condition. After cold working, stress corrosion resistance is improved by re-ageing at the precipitation hardening temperature. Hot Working of Stainless Steels Hot working of 17-4 PH should be performed at 950°-1200°C. After hot working, full heat treatment is required. This involves annealing and cooling to room temperature or lower. Then the component needs to be precipitation hardened to achieve the required mechanical properties. Machinability In the annealed condition, 17-4 PH has good machinability, similar to that of 304 stainless steels. After hardening heat treatment, machining is difficult but possible. Carbide or high speed steel tools are normally used with standard lubrication. When strict tolerance limits are required, the dimensional changes due to heat treatment must be taken into account Welding of Stainless Steels Precipitation hardening steels can be readily welded using procedures similar to those used for the 300 series of stainless steels. Grade 17-4 PH can be successfully welded without preheating. Heat treating after welding can be used to give the weld metal the same properties as for the parent metal. The recommended grade of filler rods for welding 17-4 PH is 17-7 PH.

Applications of Stainless Steels Due to the high strength of precipitation hardening stainless steels, most applications are in aerospace and other high-technology industries. Applications include: ·         Gears ·         Valves and other engine components ·         High strength shafts ·         Turbine blades ·         Moulding dies ·         Nuclear waste casks Supplier Data by Aalco

Source: Aalco, azom.com