申博体育开户 - 申博体育网站

申博体育开户 - 申博体育网站

 

Stainless steel plate

310/310S alloy (UNS S31000/S31008) alloy austenitic stainless steel is mainly used in high temperature environment。Its high chromium and nickel content ensures good corrosion resistance and oxidation resistance。It is stronger at room temperature than austenitic 304 alloy。


3/16" 1/4" 5/16" 3/8" 1/2" 5/8" 3/4" 1"
4.8mm 6.3mm 7.9mm 9.5mm 12.7mm 15.9mm 19mm 25.4mm
 
1 1/4" 1 1/2" 1 3/4" 2" 2 1/4" 2 1/2" 3"
31.8mm 38.1mm 44.5mm 50.8mm 57.2mm 63.5mm 76.2mm

General attributes

309/309S and 310/310s austenitic stainless steels are often used in high-temperature applications。Its high chromium and nickel content ensures good corrosion resistance and oxidation resistance, with slightly higher strength at room temperature compared to austenitic 304 alloy。

应用

High alloy stainless steels generally exhibit good high temperature strength, resistance to creep and environmental corrosion。Therefore, they are widely used in heat treatment industry furnace parts, such as: conveyor belt, drum, furnace head, refractory plate, pipe hanger and so on。These grades are also used in the chemical processing industry to carry hot concentrated acids, ammonia and disulphides。In the food processing industry, these grades are used in contact with thermoacetic acid and citric acid。

化学成分

Unless otherwise stated, the following chemical composition is according to ASTM A167 and ASTM A240 standards。

  309合金 309 s alloy
  (UNS S30900) (UNS S30908)
C 0.20 0.08
Mn 2.00 2.00
P 0.045 0.045
S 0.030 0.030
Si 0.75 0.75
Cr 22.00 Minimum value /24.00 maximum 22.00 Minimum value /24.00 maximum
Ni 12.00 Minimum value /15.00 maximum 12.00 Minimum value /15.00 maximum
Fe The rest The rest
  310合金 310 s alloy
  (UNS S31000) (UNS S31008)
C 0.25 0.08
Mn 2.00 2.00
P 0.045 0.045
S 0.030 0.030
Si 1.75 1.50
Cr 24.00 Minimum value /26.00 maximum 24.00 Minimum value /26.00 maximum
Ni 19.00 Minimum value /22.00 maximum 19.00 Minimum value /22.00 maximum
Fe The rest The rest

The values in the table indicate 100% weight and are the maximum values unless otherwise specified

物理性能

  309合金
密度 lbm/in3 g/cm3
    68°F (20°C) 0.29
8.03
Coefficient of thermal expansion (mIn/in) • ° F (mM/m), ° K
     68 - 212°F
    (20 - 100°C)
8.7 15.6
    68 - 932°F
    (20 - 500°C)
9.8 17.6
    68 - 1832°F
    (20 - 1000°C)
10.8 19.4
The resistivity mW•in mW•cm
     68°F (20°C) 30.7 78.0
    1200°F (648°C) 45.1 114.8
Thermal conductivity Btu/hr, ft, ° F W/m. K
    68 - 212°F
    (20 - 100°C)
9.0 15.6
     68 - 932°F
    (20 - 500°C)
10.8 18.7
比热 Btu/lbm•°F J/kg, K
    32 - 212°F
    (0 - 100°C)
0.12 502
Magnetic conductivity (annealing)1  
    200H 1.02
Elasticity coefficient (annealing)2 psi GPa
    Tension (E) 29 x 106
200
    Distortion (G) 11.2 x 106 77
  310合金
密度 lbm/in3 g/cm3
    68°F (20°C) 0.29
8.03
Coefficient of thermal expansion (mIn/in) • ° F (mM/m), ° K
     68 - 212°F
    (20 - 100°C)
8.8 15.9
     68 - 932°F
    (20 - 500°C)
9.5 17.1
     68 - 1832°F
    (20 - 1000°C)
10.5 18.9
The resistivity mW•in mW•cm
     68°F (20°C) 30.7 78.0
    1200°F (648°C) -- --
Thermal conductivity Btu/hr, ft, ° F W/m. K
    68 - 212°F
    (20 - 100°C)
8.0 13.8
    68 - 932°F
    (20 - 500°C)
10.8 18.7
比热 Btu/lbm•°F J/kg, K
    32 - 212°F
    (0 - 100°C)
0.12 502
Magnetic conductivity (annealing)1  
    200H 1.02
Elasticity coefficient (annealing)2 psi GPa
   受拉 (E) 29 x 106
200
    Distortion (G) 11.2 x 106 77

 

短期机械性能

All tensile tests are performed according to ASTM E8。The data in the table are the average results of several test samples (minimum 2 samples, maximum 10 samples)。The yield strength is through 0.The 2% offset method。Plastic elongation was measured with a 2-inch sample。

309合金

Test temperature The bending strength
(°F) (°C) ksi MPa
77 25 42.0 290
400 204 35.0 241
800 427 30.0 207
1000 538 24.0 166
1200 649 22.0 152
1400 760 20.0 138
1600 871 18.5 128
1800 982 -- --
Test temperature Tensile strength elongation
(°F) (°C) ksi MPa %
77 25 90.0 621 49
400 204 80.0 552 46
800 427 72.0 497 40
1000 538 66.0 455 36
1200 649 55.0 379 35
1400 760 36.0 248 40
1600 871 21.0 145 50
1800 982 10.1 69 65

309 s alloy

Test temperature The bending strength
(°F) (°C) ksi MPa
77 25 50.9 351
200 93 44.7 308
400 204 37.4 258
600 316 33.4 230
800 427 29.6 204
900 482 30.4 210
1000 538 26.7 184
1100 593 26.5 182
1200 649 24.7 170
1300 704 23.7 163
1400 760 22.2 153
1500 816 20.1 138
1600 871 16.6 114
1700 927 13.1 90
1800 982 8.2 56
1900 1038 4.6 32
Test temperature Tensile strength elongation
(°F) (°C) ksi MPa %
77 25 97.1 670 44.6
200 93 88.8 612 29.0
400 204 81.7 563 34.5
600 316 80.2 553 31.6
800 427 77.1 531 32.1
900 482 74.7 515 32.0
1000 538 71.2 491 26.6
1100 593 65.6 452 25.5
1200 649 55.9 386 28.8
1300 704 55.7 384 --
1400 760 36.0 248 22.5
1500 816 24.7 170 64.8
1600 871 20.7 142 73.3
1700 927 15.4 106 78.7
1800 982 10.8 74 --
1900 1038 6.6 46 --

310合金

Test temperature The bending strength
(°F) (°C) ksi MPa
77 25 42.4 292
400 204 31.5 217
800 427 27.2 188
1000 538 24.2 167
1200 649 22.6 156
1500 816 19.7 136
1800 982 -- --
2000 1093 -- --
Test temperature Tensile strength elongation
(°F) (°C) ksi MPa %
77 25 89.5 617 45
400 204 76.6 528 37.5
800 427 74.8 516 37
1000 538 70.1 483 36
1200 649 57.2 394 41.5
1500 816 30.3 209 66
1800 982 11.0 76 65
2000 1093 7.0 48 77

310 s alloy

Test temperature The bending strength
(°F) (°C) ksi MPa
77 25 45.6 314
200 93 41.4 286
400 204 36.9 254
600 316 34.6 239
800 427 30.3 209
1000 538 29.4 203
1200 649 25.8 178
1400 760 21.4 147
1600 871 16.1 111
1800 982 8.2 56
2000 1093 4.0 27
Test temperature Tensile strength elongation
(°F) (°C) ksi MPa %
77 25 90.5 624 42.6
200 93 83.4 575 41.3
400 204 77.3 533 35.8
600 316 75.2 519 35.0
800 427 73.6 508 33.5
1000 538 70.2 484 37.0
1200 649 57.0 393 32.0
1400 760 37.7 260 54.0
1600 871 22.5 155 56.5
1800 982 11.8 81 93.3
2000 1093 6.5 44 121.0

抗水溶液腐蚀

309/309S和310/310SThey are mainly used in high temperature environments to effectively utilize their oxidation resistance。However, these alloys also have certain corrosion resistance to aqueous solution because of their high chromium and nickel content。

The high nickel content makes these alloys slightly more resistant to chloride stress cracking corrosion than 18-8 stainless steels, although 309/309S and 310/310s austenitic stainless steels are still susceptible to this corrosion。

Applications requiring improved corrosion resistance to aqueous solutions are often used310/310SFor example, in concentrated nitric acid solution, grain boundary preferred corrosion may occur in such solution。

高温抗氧化性

In most cases, metal alloys react with the environment to some degree。The most common chemical reaction is oxidation: metal elements combine with oxygen to form oxides。Stainless steel through the local oxidation of chromium to make it has oxidation resistance, in the process of local oxidation of chromium, can form a very stable oxide (Cr2O3 chromium oxide)。As long as the chromium content of the metal is sufficient, a continuous layer of chrome oxide green can be formed on the metal surface to prevent the formation of other oxides and protect the metal。The oxidation rate is controlled by the transport of dotted particles。As the rust thickens on the surface, the oxidation rate drops dramatically because the particles travel farther。This process is called passivation, which is the process of passivation film formation。

The oxidation resistance of austenitic stainless steel can be calculated by the chromium content。High temperature resistant alloy containing at least 20% chromium (100% by weight)。Substituting a nickel component for an iron component also usually provides alloy performance at high temperatures。309/309s and 310/310s are high alloy materials, so they have good oxidation resistance。

The weight of the oxidized metal sample will increase because a certain amount of oxygen is incorporated into the oxide film of the product。One way to measure the oxidation resistance of metals is by exposing them to high temperatures for a specific period of time and then measuring changes in their weight。The more weight increase, the more serious surface oxidation。

The oxidation process is more complex than simple rust thickening。Spallation, or surface separation, is the most common problem in the oxidation process of stainless steel。Spallation is usually characterized by rapid weight loss。Several other factors can also cause spallation, including thermal cycling, mechanical damage, and oxide thickness。

During oxidation, chromium is present in the rust in the form of chromium oxide。When the scale is peeled off, the unoxidized metal is exposed and the oxidation rate of the material is temporarily increased due to the formation of new chromium oxide。When the rust spallation reaches a certain extent, the loss of chromium content may cause the heat resistance of the metal to be reduced, resulting in the rapid increase of iron oxides and nickel oxides, which is called rupture oxidation。

High temperature oxidation may cause the rust to evaporate。Chromium oxide formed on the surface of heat-resistant stainless steel, initially Cr2O3, is further oxidized to CrO3 with high steam pressure as temperatures rise further 。The oxide is then divided into two parts: the rust is thickened by the formation of Cr2O3 and thinned by the evaporation of CrO3。The ultimate tendency is to achieve a final balance between thickening and thinning so that the rust is at a constant thickness。Rust volatilization becomes a prominent problem at temperatures above 2000°F (1093°C) and is further exacerbated by the action of flowing gases。

其他形式的退化

In addition to oxygen, particles can also cause accelerated degradation of stainless steel at high temperatures。The presence of sulfur can cause sulphide corrosion。The vulcanization corrosion of stainless steel is a complex process, and is greatly affected by the sulfur and oxygen content and the presence of sulfur (e.g. gaseous, sulfur oxide, hydrogen sulfur).。Chromium forms stable oxides and sulfides。In the presence of oxygen and sulfur-containing compounds, a chromium oxide layer is usually formed on the outside as a protective layer to keep the sulfur out。However, sulphide corrosion can still occur where rust is damaged and separated, and in certain cases sulphur can pass through chromium oxide to form chromium sulphide inside the metal。In alloys with high nickel content (25% or more), vulcanization is enhanced。Nickel and nickel sulfide form eutectic phase with low melting point, which may cause serious damage to the material at high temperature。

The presence of carbon-rich particles in the environment causes carbon to enter the metal, which then forms internal carbides。Carburizing generally occurs at temperatures above 1470°F (800°C)。Internal carburizing metal can cause changes in mechanical and physical properties。Normally, oxygen can keep carbon out by forming a protective film on a metal surface。Higher nickel content and silicon content can reduce carburization to a certain extent。Metal dust is a particular form of carburization and usually occurs in the lower temperature range (660-1650°F or 350-900°C)。Metal dust converts solid metal through a complex mechanism into a mixture of graphite and metal particles, which in turn creates deeper pits that eventually lead to localized corrosion。

Nitriding may occur in the presence of nitrogen gas。Oxides are generally more stable than nitrides, and therefore, in an oxygen-containing atmosphere, oxide crust is usually formed。This protective film is very good at blocking nitrogen entry, so in the atmosphere and gaseous combustion products environment, there is little need to consider the effect of nitriding。In pure nitrogen, especially in dry, cracked ammonia, where the oxygen content is very low, nitriding may occur。Nitride films can be formed on metal surfaces at relatively low temperatures。At high temperatures above 1832°F or 1000°C), the diffusion of nitrogen can rapidly penetrate metal and form internal nitrides at grain boundaries, affecting the mechanical properties of metal。

Metallographic instability, the formation of new metallography at high temperature exposure, can in turn affect mechanical properties and reduce corrosion resistance。Carbide particles often precipitate (sensitize) at grain boundaries when austenitic stainless steels are cooled slowly in the temperature range 800-1650°F (427-899°C)。The higher the chromium and nickel content, the less soluble the carbon is, meaning it is more susceptible to sensitization。In this temperature range, forced quenching is recommended, especially for thicker materials。As the carbon content decreases, the time and temperature for chromium carbide formation increases。Therefore, the low carbon grade of these alloys is more resistant to sensitization, but not completely immune to the effects of sensitization。When the heating temperature reaches 1200 -- 1850°F (649-1010°C) for a long period, 309/309s and 310/310s exhibit reduced ductility at room temperature due to the influence of the Sigma phase and carbide。The Sigma phase usually forms at grain boundaries and affects the ductility of metals。This side effect can be eliminated by reannealing at a specified temperature。

Much of the high temperature degradation is influenced by the atmosphere and other operating environments。General oxidation data can only be used to estimate the oxidation resistance of different alloys。If necessary, Sunmire Steel can provide you with data and experience on oxidation resistance for specific applications。

加工特性

309/309S,310/310SStainless steel is widely used in heat treatment/processing industry because of its high temperature resistance and oxidation resistance。Because of this, these alloys are often processed into complex structures。The machinability of carbon steel is generally considered the standard in metal forming operations。Austenitic stainless steel shows very different properties from carbon steel: austenitic stainless steel is more difficult to work and hardens very quickly。Although this does not change the general processing methods we use, such as cutting, machining, molding, etc., these characteristics do affect the details of these processing methods。

Standard technique for cutting and machining ordinary mild steel, with minor modifications may also be used for machining austenitic stainless steel。But austenitic stainless steel is harder to work and hardens very quickly。The chips produced during processing are thin and hard and retain considerable ductility。Tools should be kept sharp and hard。For hardened areas, deep and slow cuts are generally used。Due to the low thermal conductivity and high coefficient of thermal expansion of austenitic stainless steel, heat removal and dimensional tolerances must be considered during cutting and machining。

Austenitic stainless steel can be formed by bending, drawing forming, rolling forming, hammering forming, flaring/flange processing, rotation, fine pumping, hydroforming and other methods to achieve cold forming。In the process of processing, austenitic stainless steel is easy to harden, the performance of the processing process to increase the processing force。This means the use of more powerful forming equipment and ultimately limits the degree of forming。

Because of various environmental and metallurgical factors, the temperature range used for 309 and 310 hot works is relatively narrow。The initial temperature range for forging is 1800-2145°F (980-1120°C) and the end temperature cannot be lower than 1800°F (980°C).。Processing at excessively high temperatures results in a decrease in the thermoplasticity of the alloy due to environmental and metallurgical factors, especially the formation of ferrite。It is processed at too low a temperature to form a second phase, such as sigma phase。After forging, the forgings need to be cooled quickly to dark heat。

焊接

The austenite grade is considered the easiest to weld in stainless steel。They can be welded in all the usual ways。309/309s, 310/310s。If filler filler is required, it is generally selected with matching ingredients。Because this grade of alloy content increases, can reduce molten pool fluidity。If the flow of the molten pool still needs to be reduced, silicon-based solder (e.g. ER309Si, ER309LSi) can be used.。

309/309s and 310/310s have high coefficient of thermal expansion and low thermal conductivity. A small amount of ferrite will form in the cured welding metal, which may lead to thermal cracks。This problem is in the anti-off welding joints, wide welding joints may be more serious。Solder with low alloy content (e.g. ER308) can increase ferrite in surfacing and reduce the tendency of thermal cracking。Diluting the composition of the base metal may reduce the corrosion and heat resistance of the solder joint。

Grade S has a relatively low carbon content。With proper welding, intergranular corrosion of the HEAT affected zone is unlikely。Removal of tempering color and rust restores corrosion resistance near the solder joint。Use stainless steel brush grinding and scrubbing, can remove backfire color and rust。Pickling can also remove rust。Small pieces of material can be placed in a tank for pickling, large pieces of material can be locally cleaned with a special mixture of nitric acid, hydrofluoric acid and hydrochloric acid。After pickling, thoroughly wash the pickling residue with clean water。

热处理/退火

The main reason for annealing these alloys is to produce a recrystallized fine structure to achieve uniform grain size and to decompose harmful chromium carbide precipitates。To ensure complete annealing, the material must be placed in the temperature range of 2050-2150°F (1120-1175°C) for approximately 30 minutes per inch of thickness。This is just general practice。Special cases may require special treatment。After proper annealing, these grades are predominantly austenitic at room temperature, with small amounts of ferrite possibly present。

309/309S,310/310SIt is inevitable to produce oxide scale during air annealing。Rust is rich in chromium and has some adhesion。Generally speaking, annealed rust is removed before further processing。There are two ways to remove rust: mechanical and chemical。A combination of surface blasting and chemical derusting is usually the most effective way to remove all stubborn rust。Silica sand and glass beads are good sandblasting materials。Iron pellets or steel pellets can also be used, but this may cause free iron to enter the surface of the metal and cause rust or discoloration。

Chemical derusting usually uses a mixture of nitric and hydrofluoric acid。Chemical tank solution and processing temperature usually depend on the actual situation。Common tank solutions include aqueous solutions of 5-15%HNO3 (65% initial strength) and _-3% HF (60% initial strength)。Too high a concentration of hydrofluoric acid can cause excessive derusting。Tank temperature is usually from room temperature to 140°F (50°C)。 Too high temperature will lead to too fast derusting, and the trough will erode the grain boundary, resulting in grooves on the metal surface。After pickling, thoroughly wash the pickling residue with water, and then dry it to avoid spot stains on the metal surface。

Due to 309/309 SEC,310/310SIt exhibits austenitic structure at room temperature and therefore cannot be hardened by heat treatment。Higher mechanical strength can be achieved by hot or cold work, but these grades usually do not achieve this state。Better tensile and yield strengths can also be obtained by cold working, which, without annealing, is not stable at the high temperatures for which these alloys are often used。If the cold made material is used in high temperature environment, but the opposite, it will affect the creep property of the material。

ml>