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Stainless steel plate

Myer Steel's 304H stainless steel plate inventory is complete in specification, thickness from 3/16" to 6-1/2" inch, 1/8" in increments。It can be delivered to your door at any time to meet your company's needs。

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

304H alloy (UNS S30409) stainless steel is 18% chromium, 8% nickel 304 austenitic deformation products。 The carbon content in this product is controlled to zero.04-0.10, improve the high temperature strength of the product components at temperatures higher than 800°F。This alloy has a wide range of uses, strong corrosion resistance and easy assembly。

一般属性

Alloy 304 (S30400), 304L (S30403), and 304H The stainless steel (S30409) is several variants of 18% chromium, 8% nickel austenitic alloy, which is the most common and most commonly used alloy in the stainless steel family。Because these alloys have one or more of the following properties, they can be used for a variety of applications。Attributes include:

  • 耐腐蚀
  • Prevention of product contamination
  • antioxidant
  • Easy processing
  • Good formability
  • Delicate appearance
  • Easy to clean
  • High strength, low weight
  • Good strength and toughness at low temperature
  • Multiple product forms already exist

Each alloy has a good combination of corrosion resistance and good processing。This combination of properties is why the alloy is so widely used, accounting for almost half of all U.S. stainless steel production。18-8 stainless steel, mainly 304,304 L,304HAnd exist in many forms, including slices, strips and plates。These alloys are commonly used in the manufacture of equipment. Examples of applications include: food and beverage, hygiene, refrigeration, and pressure vessels。

Argon oxygen decarbonization (AOD) technology achieved low carbon level at low cost, and 304 became the standard alloy。304L is used for welding products that may be exposed to conditions that cause irregular corrosion。

304HThe alloy is an improvement of 304 and has a carbon content of 0.04-0.10 for parts to be exposed to temperatures above 800°F, 304H helps to improve strength at high temperatures。

化学成分

ASTM A240 and ASME SA-240:

成分

Weight percentage maximum listed in the table unless otherwise specified

  304 304L 304H
0.08 0.030 0.04-0.01
2.00 2.00 2.00
0.045 0.045 0.045
0.030 0.030 0.030
0.75 0.75 0.75
18.00
20.00
18.00
20.00
18.00
20.00
8.0
10.50
8.0
12.00
8.0
10.5
0.10 0.10 0.10

The data in the above table are only typical component analysis and cannot be used as the maximum or minimum value of the final product component。The composition of a specific piece of material may be inconsistent with the above data。

耐腐蚀

Uniform corrosion
Austenitic stainless steel 304,304L,304HCorrosion resistance in moderate oxidation and reduction environments。These alloys are widely used in processing and processing food and beverages, dairy equipment and appliances。These alloys can be used in heat exchangers, pipelines, oil tanks, and other processing equipment in contact with fresh water。

These alloys have a chromium content of 18-19% and are resistant to oxidation in an oxidizing environment。The table below shows the oxidation rate of 304 alloy in dilute nitric acid

% 硝酸 温度

°F (°C)
The corrosion rate

Mils/Yr (mm/a)
10 300 (149) 5.0 (0.13)
20 300 (149) 10.1 (0.25)
30 300 (149) 17.0 (0.43)

304,304L,304HIt is also resistant to moderate organic acids such as acetic acid and reductive acids such as phosphoric acid。18-8 alloys contain 9-11% nickel and are resistant to moderate reduction environments。More reductive environments, such as boiling dilute hydrochloric acid and sulfuric acid, are too aggressive for these materials。Even if it's semi-boiling, it's too corrosive。

In some cases, the corrosion rate of low carbon 304L alloy is lower than that of high carbon 304 alloy。Data from formic acid, sulfamic acid and sodium hydroxide confirm this。In addition, 304,304L, 304H performance is the same in most corrosive environments。A notable special case is that 304L alloy is preferred in an environment sufficient to cause intergranular corrosion in the welding and heat affected zones, because its low carbon content helps to resist intergranular corrosion。

Intergranular corrosion
18-8 austenitic stainless steel 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。The carbon content of 304 alloy causes sensitization in the heat state during gas welding and heat affected zone welding。Therefore, 304L alloy with low carbon content is usually selected when the material is used in the post-welding state。The low carbon content prolongs the time for chromium carbide to precipitate to hazardous levels, but the long-term presence of the material in the precipitation temperature range does not completely eliminate this precipitate。

Intergranular corrosion test
ASTM A262

Assessment test
Corrosion rate, Mils/Yr (mm/a)
304 304L

Practice E
Base metal welding

After welding

Bending without cracking

There are some cracks in the welding
(Not accepted)

There is no crack

There is no crack

Practice A
Base metal welding

After welding
S-level structure 起沟
(Not accepted)

The level of structure

The level of structure

Stress corrosion cracking
304,304 L, 304H alloys are the most susceptible to stress corrosion cracking (SSC) of austenitic stainless steels because of their relatively low nickel content。The conditions that cause stress corrosion cracking are :(1) the presence of halide ions (usually chloride), (2) residual tension, and (3) temperatures above 120°F (49°C)。Cold deformation, drawing into tubesheet and welding can all produce stress during alloy forming。Annealing and stress-relieving heat treatment after cold deformation can reduce the stress, thus reducing the possibility of halide stress corrosion cracking。In the environment that may cause intergranular corrosion, it is best to choose low carbon 304L alloy material under low temperature annealing。

Halides (Chloride stress corrosion Test)
测试 U-bend (high compression) sample
304

33% lithium chloride,

沸腾

Base metal welding

After welding

Rupture, 14-96 hours

Rupture, 18-90 hours

26% sodium chloride,

沸腾

Base metal welding

After welding

Fracture, 142-1004 hours

Fracture, 300-500 hours

40% calcium chloride,

沸腾

Base metal welding Fracture, 144 hours

--

The surrounding environment

Exposure to coastal environments
Base metal welding

After welding

No fault

No fault

Spot/gap corrosion
18-8 alloys have been used very successfully in fresh water with low chloride content。In general, especially if gaps are present, the limit for 18-8 alloys is 100ppm chloride。High concentrations of chloride may cause gap and spot corrosion。Under more severe conditions, such as low PH, or high temperatures, alloys with higher molybdenum content, such as 316, may be considered。18-8 alloys are also not recommended for use in Marine environments。

物理性能

密度
0.285 lb/in3 (7.90 g/cm3)

Modulus of tensile elasticity
29 x 106 psi (200 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 16.6 x 10-6
18 - 1600 20 - 870 11.0 x 10-6 19.8 x 10-6

Heat conduction

Temperature range Btu/hr/ft / ° F W/m/K
°F °C
212 100 9.4 16.3
932 500 12.4 21.4

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 J/kg/K
32-212 0-100 0.12 500

Magnetic permeability
18-8 alloys are non-magnetic in the annealed state, and the permeability is generally less than 1 at 200H.02。The permeability varies depending on the composition of the metal。By cooling, the permeability can be increased。

Cold working percentage Magnetic permeability
304 304L
0 1.005 1.015
10 1.009 1.064
30 1.163 3.235
50 2.291 8.480

机械性能

Mechanical properties at room temperature
Annealed 304 and 304L austenitic stainless steel plates, ASTM A240, ASME SA-240, require minimum mechanical properties as shown in the table below:

性能 ASTM A240 and ASME SA-240

Minimum mechanical properties required
304 304L 304H
0.2% 抵消
Yield strength,
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
硬度,
最大.,
Brinell hardness)
 RB


201
92


201
92


201
92

Performance at low temperature and temperature
Short-term tensile properties at low temperature and temperature are shown in the following table。The temperature reaches 1000°F (538°C) or above, stress cracking should be considered. Stress cracking data are also shown in the table below。

Test temperature

0.2% yield strength

°F °C psi (MPa)
-423 -253 100,000 690
-320 -196 70,000 485
-100 -79 50,000 354
70 21 35,000 240
400 205 23,000 160
800 427 19,000 130
1200 650 15,500 105
1500 815 13,000 90

Tensile strength 延伸
psi (MPa) The percentage
250,000 1725 25
230,000 1585 35
150,000 1035 50
90,000 620 60
70,000 485 50
66,000 455 43
48,000 330 34
23,000 160 46

The impact resistance
Annealed austenitic stainless steel is used for liquefied natural gas and other cryogenic applications due to its high impact resistance even at low temperatures, coupled with low temperature hardness and machinability。The data of Xia's V-shaped impact test are shown in the table below

温度 Xia V - shaped impact experiment energy absorption
°F °C 英尺 ? 磅 焦耳
75 23 150 200
-320 -196 85 115
-425 -254 85 115

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 the actual operation, the fatigue strength will also be affected by other factors, such as: increasing the smoothness of the surface can increase the fatigue strength, and increasing the corrosive environment can reduce the fatigue strength。

焊接

Austenitic stainless steel is considered to be the easiest alloy steel to weld and can be welded with all fusions as well as resistance welding。304,304 L is a typical austenitic stainless steel。

Two factors are considered when producing welded contacts for austenitic stainless steel: 1) to maintain corrosion resistance and 2) to avoid cracking。

As the material is welded, a temperature ladder is formed, from the melting temperature of the pool to the surrounding temperature slightly away from the welding point。The higher the carbon content of the welding material is, the more likely the welding thermal cycle will lead to chromium carbide precipitation, which has an impact on the corrosion resistance of the material。In order to keep the corrosion resistance of the material at the best level, the low carbon material (304L) should be selected for operation in the welded state.。Alternatively, complete annealing is used to dissolve chromium carbide, restoring a high level of corrosion resistance to materials with a standard carbon content。

Welded metal with complete austenitic structure is more prone to crack formation during welding operation。Therefore, a small amount of ferrite was added to the 304 and 304L alloys to reduce the crack sensitivity of the material and achieve the effect of resolidification。

When welding 18-8 austenitic alloy to carbon steel, 309 alloy (23% chrome-13) is usually used.5% nickel) or nickel based solder。

热处理

The side effects of cold forming and precipitated chromium carbide can be removed by heat treatment of austenitic stainless steel。The best heat treatment to meet these requirements is solid melt annealing in the temperature range of 1850°F to 2050°F (1010°C to 1121°C)。Cooling from the annealing temperature at 1500-800°F (816° C-427 °C) should be sufficient to avoid chromium carbide reprecipitation。

These materials cannot be hardened by heat treatment。

清洁

Regardless of corrosion, the surface of stainless steel should be kept clean during processing and use。

During welding, inert gas processing is adopted. Rust and slag formed during welding are removed by stainless steel brush。A normal carbon steel brush will leave carbon steel particles on the surface of stainless steel, which will eventually cause the surface to rust。Under strict conditions, the welding area is treated with a derusting solution (such as a mixture of nitric and hydrofluoric acid) that washes away rust and slag formed during the welding process。

Inland, light industrial materials require less maintenance, with only sheltered areas sometimes needing to be cleaned with pressurized water。Heavy industry recommends frequent cleaning to remove accumulated dust, which can eventually cause corrosion and damage the surface appearance of stainless steel。

Stubborn stains and deposits can be scrubbed with scrub and fiber brushes, sponges, and stainless steel lint。Stainless steel fleece will leave permanent scratches on smooth stainless steel surfaces。

Many stainless steels need to be cleaned and disinfected regularly。The equipment is usually cleaned with special caustic soda, organic solvent, acidic solution (phosphoric acid or sulfuric acid)。Strong reducing acids, such as hydrofluoric or hydrochloric acid, may damage stainless steel。

After solution cleaning, rinse stainless steel thoroughly with water。

Proper design facilitates cleaning。With rounded Angle, inner rounded Angle, seamless equipment, is conducive to cleaning and surface polishing。