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Stainless steel plate

Sunmire Steel is the largest single stockholder of stainless steel plates in North America, increasing in thickness from 3/16" to 6-1/2" inch by 1/8" inch。304 stainless steel can be e-Z drilling to improve machinability。

3/16" 1/4" 5/16" 3/8" 7/16" 1/2" 9/16" 5/8" 3/4" 7/8" 1" 1 1/8"
4.8mm 6.3mm 7.9mm 9.5mm 11.1mm 12.7mm 14.3mm 15.9mm 19mm 22.2mm 25.4mm 28.6mm
 
1 1/4" 1 3/8" 1 1/2" 1 5/8" 1 3/4" 2" 2 1/4" 2 1/2" 2 3/4" 3" 3 1/4" 3 1/2"
31.8mm 34.9mm 38.1mm 41.3mm 44.5mm 50.8mm 57.2mm 63.5mm 69.9mm 76.2mm 82.6mm 88.9mm
 
3 3/4" 4" 4 1/4" 4 1/2" 4 3/4" 5" 5 1/4" 5 1/2" 5 3/4" 6"
95.3mm 101.6mm 108mm 114.3mm 120.7mm 127mm 133.4mm 139.7mm 146.1mm 152.4mm

Alloy 316 (UNS S31600) and 316L (UNS S31603) are austenitic stainless steels based on molybdenum, This stainless steel is compared with conventional chrome-nickel austenite such as 304 alloy,Better resistance to general corrosion and spot corrosion, crack corrosion。These alloys have higher ductility, stress corrosion resistance, compressive strength and high temperature resistance。In addition to excellent corrosion resistance and strength, 316 alloy and 316L copper-nickel-molybdenum alloy have excellent assembly and formability characteristic of austenitic stainless steel。

般属性

合金316 (UNS S31600), 316L(S31603), 317L(S31703) is an austenitic stainless steel based on molybdenum, Compared with conventional chrome-nickel austenite such as 304 alloy,Better resistance to general corrosion and spot corrosion, crack corrosion。These alloys have higher ductility, stress corrosion resistance, compressive strength and high temperature resistance。In applications requiring better resistance to general and pitting corrosion, 317L is preferred over 316 or 316L because 317L contains 3-4% molybdenum, while 316 and 316L contain only 2-3% molybdenum。

316 alloy and 316L and 317L copper-nickel-molybdenum alloy also have the typical characteristics of austenitic stainless steel, that is, good machinability and formability。

化学成分

化学成分 ASTM A240, ASME SA-240 are listed below

 

Weight percentage maximum shown in the table unless otherwise specified

成分 Alloy 316 Alloy 316L Alloy 317L
0.08 0.030 0.030
2.00 2.00 2.00
0.75 0.75 0.75
16.00
18.00
16.00
18.00
18.00
20.00
10.00
14.00
10.00
14.00
11.00
15.00
2.00
3.00
2.00
3.00
3.00
4.00
0.045 0.045 0.045
0.030 0.030 0.030
0.10 0.10 0.10
Balance Balance Balance

耐腐蚀

General corrosion
Compared to 18-8 stainless steel, 316,316 L and 317L have better corrosion resistance in atmospheric and other mild environments。In general, media that do not corrode 18-8 stainless steel will not corrode grades of molybdenum。The only exception is highly oxidizing acids, such as nitric acid, to which molybdenum-containing stainless steel is less resistant。

In sulfuric acid solution, 316 and 317L have better corrosion resistance than other chromium-nickel type grades。At temperatures up to 120°F (38°C), both grades have good corrosion resistance to high concentration solutions。Of course, testing during use is essential, as operating conditions and acid contaminants can significantly affect the corrosion rate。These two grades offer better corrosion resistance than other types of stainless steel when concentrating sulphur-containing gases。However, in such applications the acid concentration has a considerable effect on the corrosion rate and this factor should be considered carefully。

Molybdenum-containing stainless steel 316 and 317L, corrosion resistance to a variety of other environments。The corrosion data below show that these alloys exhibit superior corrosion resistance in boiling 20% phosphoric acid solution。They are also widely used in the treatment of thermal organic acids and fatty acids。Stainless steel containing molybdenum is commonly used in the manufacture and processing of food and medical products to minimize metal contamination。

Generally speaking, under the same environmental conditions, the performance of 316,316 L can be regarded as equivalent to that of 317L。Exceptions are made in the case of intergranular corrosion in the weld, heat affected zone。In such media, 316L and 317L are more often chosen because of their low carbon content and improved intergranular corrosion resistance。

Corrosion resistance in boiling solution

Boiling test

Annual corrosion rate (mm/y)
Alloy 316L Alloy 317L
Base
Metal
Welded Base
Metal
Welded
20%
乙酸
0.12
(0.003)
0.12
(0.003)
0.48
(0.012)
0.36
(0.009)
45%
甲酸
23.4
(0.594)
20.9
(0.531)
18.3
(0.465)
24.2
(0.615)
1%
盐酸
0.96
(0.024)
63.6
(1.615)
54.2
(1.377)
51.4
(1.306)
10%
草酸
48.2
(1.224)
44.5
(1.130)
44.9
(1.140)
43.1
(1.094)
20%
磷酸
0.60
(0.15)
1.08
(0.027)
0.72
(0.018)
0.60
(0.015)
10%
Amino sulfonic acid,
124.2
(3.155)
119.3
(3.030)
94.2
(2.393)
97.9
(2.487)
10%
硫酸
635.3
(16.137)
658.2
(16.718)
298.1
(7.571)
356.4
(9.053)
10%
Sodium bisulfate
71.5
(1.816)
56.2
(1.427)
55.9
(1.420)
66.4
(1.687)
50%
Sodium hydroxide
77.6
(1.971)
85.4
(2.169)
32.8
(0.833)
31.9
(0.810)

Spot/gap corrosion
The corrosion resistance of austenitic stainless steel in chloride or other halogen ions can be improved by increasing the content of chromium, molybdenum and nitrogen。Pitting is calculated by PREN (pitting equivalent), PRE = Cr+3.3Mo+16N。The PREN of 316L =24.2, PREN of 304 =19.0, this reflects that 316 (or 316L) has better corrosion resistance than 304。317L, molybdenum content 31%, PREN=29.7, indicating better corrosion resistance than 316。

304 stainless steel is resistant to spot and gap corrosion in water containing 100ppm chloride。The 316 and 317L containing molybdenum are resistant to spot and gap corrosion in water containing 2000ppm and 5000ppm chloride, respectively。Although both alloys have shown some success in seawater (19000ppm chloride), their use is not recommended。2507 alloys, 4% molybdenum, 25% chromium and 7% nickel are designed for use in saltwater environments。316,317 L is only suitable for some Marine environment applications, such as ship guide, offshore building exterior walls, etc。316,317 L alloy showed no corrosion in 100 h 5% salt spray test (ASTM B117)

Intergranular corrosion
316,317 L alloy exposed to 800°F to 1500 ° F (427°C至 816°C) At temperature, chromium carbide may precipitate at grain boundaries。This type of stainless steel is susceptible to intergranular corrosion when exposed to harsh conditions。However, during short exposures, such as welding, 317L is more resistant to intergranular corrosion than 316 due to its higher chromium and molybdenum content。When the welding thickness exceeds 11.At 1mm, even 317L alloy, also need to do annealing treatment。

If annealing treatment cannot be done after welding or low temperature stress relief treatment is needed, using 316L and 317L can effectively avoid intergranular corrosion。Both alloys are corrosion-resistant in the welded state and exposed to temperatures in the 800 to 1500°F (427 to 826°C) range。For containers requiring stress relief treatment, a short time of treatment within this temperature range will not affect the normal corrosion resistance of the metal。L grade large steel after annealing, do not need to do high temperature accelerated cooling treatment。

316L and 317L have the same corrosion resistance and mechanical properties as their counterparts with high carbon content. These two alloys have additional advantages in applications where intergranular corrosion is likely to occur。Although the transient heat encountered during welding and stress relief is insufficient to cause intergranular corrosion, it is worth noting that continuous or prolonged exposure to temperatures ranging from 800 °F to 1500°F (427 to 826°C) is harmful for both alloys。Stress relief treatments in the temperature range 1100 to 1500°F (593 to 816°C) may cause mild embrittlement of these alloys。

Intergranular corrosion test

ASTM A262
Assessment test

Corrosion rate, Mils/Yr (mm/a)
Alloy 316 Alloy 316L Alloy 317L
Practice B
Base metal welding
After welding

36 (0.9)
41 (1.0)

26 (0.7)
23 (0.6)

21 (0.5)
24 (0.6)
Practice E
Base metal welding

After welding

No Fissures
on Bend
Some Fissures
on Weld (unacceptable)

No Fissures
No Fissures

No Fissures
No Fissures
Practice A
Base metal welding
After welding

Step Structure

Ditched (unacceptable)

Step Structure
Step Structure

Step Structure
Step Structure

Stress corrosion cracking
Austenitic stainless steel is susceptible to stress corrosion cracking in halogenated environment。Although 316,317 L alloys have better stress corrosion cracking resistance than 18Cr-8Ni alloys to some extent due to their molybdenum content, they are still more susceptible to influence。产生Stress corrosion cracking的条件包括:(1)卤化物的存在(一般来说是氯化物);(2)残余张应力;(3)温度超过120°F (49°C)。

Cold deformation or thermal cycling may produce stress during welding。Annealing, stress relief heat treatment can effectively reduce the stress, thus reducing the sensitivity of the material to halide stress corrosion cracking。The low carbon L grade has no special advantage in stress corrosion cracking, but is still preferred for stress relief operations where intergranular corrosion may occur。

Halides (Chloride stress corrosion Test)

测试

U-bend (high compression) sample
Alloy 316 Alloy 316L Alloy 317L
42% magnesium chloride, boiling 断裂,
424小时
断裂
21-45 小时
断裂
72 小时
33% lithium chloride, boiling 断裂
48-569 小时
断裂
21-333 小时
断裂
22-72 小时
26% sodium chloride, boiling 断裂
530-940 小时
No fault
1002 小时
断裂
小时
40% calcium chloride, boiling 断裂
144-1000 小时
-- --
Exposure to seaside environment, ambient temperature No fault No fault No fault

抗氧化性

316,317 L has good oxidation resistance, and the rust generation rate is relatively low even when the temperature reaches 1600 to 1650°F (871 to 899°C) in atmospheric environment。In general, 316 is slightly inferior to 304 stainless steel because 304 has a slightly higher chromium content (18% vs. 16%).。The oxidation rate is usually affected by the atmosphere and operating environment, so it is not possible to provide exact oxidation rate for reference。

物理性能

结构
After proper annealing, 316,317 alloy is mainly austenite。Small amounts of ferrite may be present。When cooled from 800 to 1500°F (427 to 816°C), carbides precipitate and the structure consists of austenite and carbides。

Melting range: 2450 to 2630 ° F (1390 to 1440 ° C)

密度: 0.29 lb/in3 (8.027 g/cm3)

Modulus of tensile elasticity: 29 x 106 psi (200 Gpa)

Shear modulus: 11.9 x 106 psi (82 Gpa)

Linear coefficient of thermal expansion

Temperature range

系数
°F °C In/in / ° F Cm/cm / ° C
68 - 212 20 - 100 9.2 x 10-6 16.5 x 10-6
68 - 932 20 - 500 10.1 x 10-6 18.2 x 10-6
68 - 1832 20 - 1000 10.8 x 10-6 19.5 x 10-6

Heat conduction

Temperature range

Btu, in/hr, ft2•°F W/m. K
°F °C
68 - 212 20 - 100 100.8 14.6

The total conductivity of a metal depends on other factors besides its thermal conductivity。18-8 alloy stainless steel has the ability to keep the surface clean, and compared with other metals with high thermal conductivity, 18-8 alloy tends to have better thermal conductivity。

比热

°F °C Btu/lb, ° F Jkg k.
68 20 0.108 450
200 93 0.116 485

The resistivity

合金 Data at 68°F (20°C)
Microhm-in. Microhm-cm.
316 29.1 74.0
317 31.1 79.0

Magnetic permeability
Austenitic stainless steel is non-magnetic in annealed and complete austenitic states。316,317 L in the annealing state, at 200H, the permeability is generally less than 1.02。The permeability of cold-deformed materials varies with the composition of the metal and the degree of cold deformation, but is generally higher than that of annealed materials。

机械性能

Mechanical properties at room temperature
Annealed 316,316L, 317L austenitic stainless steel plates, ASTM A240, ASME SA-240, the minimum mechanical properties required are shown in the table below:

性能 ASTM A240 and Minimum mechanical properties required by ASME SA-240
Alloy 316 (S31600) Alloy 316L (S31603) Alloy 317L (S31703)
The yield strength
0.2% 抵消
psi (MPa)
30,000
(205)
25,000
(170)
30,000
(205)
Ultimate tensile strength
psi (MPa)
75,000
(515)
70,000
(485)
75,000
(515)
Percentage of elongation (2 inches or 51mm) 40.0 40.0 40.0
Hardness, maximum, (Brinell hardness) (RB) 217
(95)
217
(95)
217
(95)

The effect of cold cooking
Cold deformation of austenitic alloy at room temperature or slightly elevated temperature can increase strength, but also reduce elongation。Flat rolled products of 316,316 and 317L are usually annealed。

Component analysis (see footnote)

合金 C Mn Cr Ni Mo
316 0.051 1.65 17.33 13.79 2.02
316L 0.015 1.84 16.17 10.16 2.11
317L 0.025 1.72 18.48 12.75 3.15

Tensile properties under heating condition
The tensile properties of 316,316L and 317L at short temperature rise are shown in the table below

Component analysis (see footnote)

合金 C Mn Cr Ni Mo
316 0.080 1.5 17.78 12.5 2.46
316L 0.015 1.84 16.17 10.16 2.11
317L 0.025 1.72 18.48 12.75 3.15

316 (Sample tensile test procedure)

Test temperature The yield strength
0.2% 抵消
Ultimate tensile strength
°F °C psi MPa psi MPa
68 20 42,000 292 82,000 568
200 93 -- -- 75,600 521
400 204 -- -- 71,400 492
600 316 -- -- 71,150 491
800 427 26,500 183 71,450 493
1000 538 23,400 161 68,400 472
1200 649 22,600 156 50,650 349
1400 760 -- -- 30,700 212
1600 871 -- -- 18,000 124
Test temperature 延伸 Percentage of area reduction
°F °C
68 20 68.0 81.0
200 93 54.0 80.0
400 204 51.0 78.0
600 316 48.0 71.0
800 427 47.0 71.0
1000 538 55.0 70.0
1200 649 24.0 32.0
1400 760 26.0 35.0
1600 871 47.0 40.0

Stress failure and creep characteristics
At temperatures above 1000°F (538°C), austenitic stainless steels should be noted for creep and stress failure. The creep and stress failure strength have different values reported by different researchers。

The impact resistance
Annealed austenitic stainless steel can maintain high impact resistance even at low temperature, coupled with low temperature hardness and processability, so it is widely used in low temperature operation。The data of Xia's V-shaped impact test are shown in the table below:

温度 Energy absorption
°F °C Ft-lb J
75 23 65 - 100 88 - 134

Fatigue strength
The maximum stress of a metal material without failure under infinite alternating loads is called fatigue strength or fatigue limit。The fatigue strength of austenitic stainless steel is generally 35% of the tensile strength。In practice, fatigue strength is also affected by other factors, such as corrosion conditions, stress patterns, surface smoothness, etc。Therefore, the exact value of fatigue limit cannot be given。

热处理

退火
Austenitic stainless steel in annealed state can be used directly。热处理 may be required during or after processing to remove side effects of cold forming and to dissolve precipitated chromium carbide。316,317 L solution annealing was performed in the temperature range of 1900 to 2150°F (1040 to 1175°C), followed by air cooling or water quenching depending on the thickness of the material。The material should be rapidly cooled from 1500 to 800°F (816 to 427°C) to avoid chromium carbide reprecipitation and to provide optimum corrosion resistance。The cooling time from annealing temperature to dark heat should be less than 3 minutes。

316,317 L cannot be hardened by heat treatment。

锻造

初始 2100 - 2200°F (1150 - 1205°C)
结束 1700 - 1750°F (927 - 955°C)

加工

Austenitic stainless steel, including 316,317 L, is usually machined into a wide variety of parts。Processing methods are perforation, forming, etc., the equipment used and processing carbon steel equipment is basically the same。The good ductility of austenitic stainless steel can be easily formed by bending, stretching, deep drawing and other methods。However, austenitic stainless steel itself strength and hardening performance is larger, so the processing of austenitic stainless steel power requirements are much larger than carbon steel。

焊接
Austenitic stainless steel is considered the easiest stainless steel to weld, and can be welded with all fusions as well as resistance welding。焊接点要考虑两个重要因素1)避免硬化裂纹;2)保持焊口和热影响区的耐腐蚀性。

Welded metal with complete austenitic structure is more prone to crack formation during welding operation。Therefore, a small amount of ferrite was added to 316,316L and 317L alloys to reduce the crack sensitivity of the material。

Low carbon 316L and 317L solder base and solders are recommended for welds used in corrosive environments。The higher the carbon content of the welding metal, the more prone to carbide precipitation (sensitization), which may lead to intergranular corrosion。Low carbon L grade, can effectively reduce and avoid sensitization。

In harsh conditions, the corrosion resistance of high molybdenum pile may be reduced due to the micro segregation of molybdenum。To overcome this side effect, the molybdenum content of the solder should be increased。317L In some harsh applications, the molybdenum content of the pile is 4% or higher。904L alloy (AWS ER 385, 4.5% Mo) or 625 alloys (AWS ErnicrMO-3, 9% Mo) are often used for this solder。

Contamination of copper and zinc should be avoided in the welding area, so these two components can form compounds with low melting points that cause welding cracks。