ASM手册热处理卷中关于不锈钢的热处理内容

在压力容器设计中，一提到奥氏体不锈钢的热处理，人们总是说不。但需要注意的是GB150或ASME只是对焊后热处理（PWHT）不作要求。笼统地说奥氏体不锈钢不能进行热处理，是不准确的。GB150要求奥氏体不锈钢在经过固溶处理后供货，这就已经是热处理了。

ASM HANDBOOK VOLUMN4: HEATTREATING 第1682页-第1703页，摘录如下：

一、传统的奥氏体不锈钢

Conventional austenitic cannot be hardenedby heat treatment but will harden as a result of cold working.

奥氏体不锈钢无法通过热处理强化，但可以通过冷加工变形强化。

These steels are usually purchased in an annealed orcold-worked state.

它们的供货状态通常是退火或冷加工

Following welding or thermal processing, a subsequent re-annealmay be required for optimum corrosion resistance, softness, and ductility.

在焊接或热加工中，为了抗腐蚀性能、软化及延展性，通常要求进行再退火。

During annealing, chromium carbides, which markedlydecrease resistance to intergranular corrosion, are dissolved.

在退火中，显著损害抗晶间腐蚀能力的碳化铬将会重新溶解。

Annealing temperatures, which vary somewhat with thecomposition of the steel（退火温度与钢材成分有关）, are given in Table 3 forwrought alloys（锻造合金）and in Table 4 for thecorresponding cast alloys（铸造合金）. Table 5 includescompositions and typical microstructures（金相组织） forselected austenitic corrosion-resistant cast steels

Because carbide precipitation can occur at temperaturesbetween 425 and 900 °C (800 and 1650 °F), it obviously is desirable that theannealing temperature should be safely above this limit.

在425至900°C会出现碳化物析出，退火温度应高于这个范围。

Moreover, because all carbides should be in solutionbefore cooling begins, and because the chromium carbide dissolves slowly, thehighest practical temperature consistent with limited grain growth is selected.This temperature is in the vicinity of 1095 °C (2000 °F).

碳化物应在冷却前溶解，又因为碳化铬溶解速度缓慢，实际的最高退火温度通常在1095 °C左右。

Cooling from the annealing temperature must be rapid, butit must also be consistent with limitations of distortion. Wheneverconsiderations of distortion permit, water quenching is used, thus ensuringthat dissolved carbides remain in solution.

冷却时，应当从退火温度开始快速冷却，若变形量允许可以采用水淬，以保证碳化物的固溶。

Because it precipitates carbides more rapidly, type 310invariably requires water quenching. Where practical considerations of distortionrule out such a fast cooling rate, cooling in an air blast is used.

因为碳化物析出较快，310不锈钢通常要求水淬，考虑到变形量，可以采用空冷。

With some thin-section parts, even this intermediate rateof cooling（中等速率的冷却） produces excessive distortion（超量变形）, andparts must be cooled in still air. If cooling in still air does not provide arate sufficient to prevent carbide precipitation（碳化铬析出）,maximum corrosion resistance will not be obtained（无法获得最大的抗腐蚀能力）. A solution to this dilemma is the use of a stabilized grade or thelow-carbon alloys.（应当改用稳定化或超低碳不锈钢。）

二、稳定化不锈钢

Stabilized austenitic alloys, namely types 321, 347, 348,and Carpenter 20Cb-3, contain controlled amounts of titanium or of niobium（含有一定量的钛Ti和铌Nb）, which render the steel nearly immune tointergranular precipitation of chromium carbide and its adverse effects oncorrosion resistance.（能够防止晶间碳化铬的析出，并抵抗晶间腐蚀）Nevertheless,these alloys may require annealing to relieve stresses, to increase softnessand ductility, or to provide additional stabilization.（若为了消除残余应力，软化金属和增加延展性，或增强稳定性，也可要求进行热处理）

To obtain maximum softness and ductility, the stabilizedgrades are annealed at the temperatures shown in Table 3.

表3给出了稳定化不锈钢获得最大软化和延展性的退火温度

Unlike the unstabilized grades, these steels do notrequire water quenching or other acceleration of cooling from the

annealing temperature to prevent subsequent intergranularcorrosion; air cooling is generally adequate.

稳定化不锈钢不要求水淬，或其他加速冷却以防止晶间腐蚀的方法，空冷足矣。

When maximum corrosion resistance of the stabilized austeniticgrades is required, it may be necessary to employ a heat treatment known as astabilizing anneal.

如果要求有最大的抗腐蚀能力，通常要求进行稳定化处理

The treatment consists of holding at 845 to 900 °C (1550to 1650 °F) for up to 5h, depending on section thickness.

热处理制度取决于工件厚度，温度范围为845 to 900 °C，保温最长5h。

It may be applied either prior to, or in the course of,fabrication, and it may be followed by short-time stress relieving at 705 °C(1300 °F) without danger of harmful carbide precipitation (see the section"Stress Relieving of Austenitic Stainless Steels" in this article).

稳定化处理可以在制造加工之前或加工制造过程中进行，并可随后在705°C进行短时的消除应力处理，若无需考虑碳化铬的析出的危害。

Carpenter 20Cb-3 stainless steel is unlike theconventional stabilized austenitics (types 321, 347, and 348) because of its higheralloy content and improved corrosion resistance. This alloy normally isstabilized and annealed at 925 to 955 °C(1700 to 1750 °F).

与321,347及348等传统的稳定化不锈钢不同，Carpenter合金 20Cb-3（即N08020）有更高的合金含量及更强抗腐蚀能力。20Cb-3合金在925~955°C这一更高的温度范围内稳定化退火。

For special applications, the alloy can be annealed athigher temperatures (up to 1150 °C, or 2100 °F), but this is permissible onlyif the alloy will not be subject to welding or heating temperatures over 540 °C(1000 °F).

（这段不懂翻）

Certain restrictions on furnace atmosphere are mandatory（接下来是对热处理炉膛气氛的要求）.Furnace combustion（炉内燃烧） must be carefully controlledto eliminate carburizing （渗碳）or excessively oxidizing （氧）conditions. Because the properties of the stabilized steels arebased on their original carbon content, carbon absorption cannot be tolerated.（碳含量会影响稳定化不锈钢的性能） Excessively oxidizing conditions cause the formation of a scale thatis difficult to remove in subsequent descaling operations.（不利于随后的除锈操作） Direct impingement of flame on the work must be prevented. （应避免火焰直接加热）The sulfur content of the furnace atmosphere, particularly inoil-fired furnaces, must be kept low;（要控制燃油中的硫含量）naturalgas, not producer gas, should be used.（要用天然气而不能用煤气）

三、低碳奥氏体不锈钢

Low-carbon austenitics are intermediate in tendency toprecipitate chromium carbides to the stabilized and unstabilized grades. Carboncontent (0.03% max) is low enough to reduce precipitation of intergranularcarbides. This characteristic of limited sensitization is of particular valuein welding, flame cutting, and other hot-working operations.

碳化铬析出的倾向性介于稳定化不锈钢和非稳定化不锈钢之间。最多0.3%的碳含量能够减少晶间碳化物的析出。这种特性对于防止焊接、火焰切割及其他热加工中的敏化具有重要的意义。

They do not require the quenching treatment（淬火处理）that unstabilized grades requireto retain carbon in solid solution.（非稳定化不锈钢要求重新固碳）

Nevertheless, the low-carbon alloys are not satisfactory for long-timeservice in the sensitizing temperature range of 540 to 760 °C (1000 to 1400 °F)because they are not completely immune to the formation of carbides deleteriousto corrosion resistance.

低碳不锈钢不宜在540 to 760 °C这一敏感的温度区间长时间使用，因为它不能完全避免有损抗腐蚀性能的碳化物的形成。

Recommended annealing temperatures for the low-carbon alloys are given inTable 3.

表3给出了退火温度。

The effects of sensitization and susceptibility to general corrosion varyamong the low-carbon alloys, depending on their chemical composition. Becausethey contain molybdenum, types 316L and 317L are susceptible to σ-phase formation as aresult of long-time exposure at 650 to 870 °C (1200 to 1600 °F).

化学成分影响抗腐蚀能力。长时间暴露于650 to 870 °C，钼能促进σ相的形成。

However, the corrosion resistance of these grades can be improved byemploying a stabilizing treatment (ASTM A 262C), consisting of holding at 885°C (1625 °F) for 2 h, prior to stress relieving at 675 °C (1250 °F). Afterreceiving the stabilizing heat treatment, these alloys pass the copper-copper sulfate16% sulfuric acid test (ASTM A 262, Practice E) for freedom from intergranularcarbide precipitation.

在675°C消除应力处理之前，进行885 °C，2h保温的热处理，能够提高抗腐蚀性能。（能够通过ASTM A 262,方法E的晶间腐蚀试验。）

四、高氮奥氏体不锈钢

High-nitrogen austenitic stainless steels are heattreated in the same manner and are subject to the same problems (carbideprecipitation and distortion) as conventional austenitics. They cannot behardened by heat treatment but

will harden by cold working.

高氮奥氏体不锈钢与传统奥氏体不锈钢一样同样有碳化物析出和变形的问题。热处理无法强化，但冷加工会出现硬化。

High-nitrogen austenitics are annealed to ensure maximumcorrosion resistance, softness, and ductility. Rapid cooling is preferred.Annealing temperature ranges are listed in Table 3.

要求快冷。

五、高合金奥氏体不锈钢

Highly alloyed austenitic stainless steels contain largeamounts of molybdenum to provide very good resistance

to chloride corrosion. （高钼，抗氯化物腐蚀）They usually are producedwith low carbon to avoid sensitization （低碳，避免敏化）and maycontain copper for increased acid resistance（铜，抗酸腐蚀）.These alloys are austenitic in the mill-annealed condition but may form σ or δferrite phases under certain conditions of heat treatment or service. Thosephases may be detrimental to corrosion resistance and mechanical properties.

轧制退火时是奥氏体，但在特定的热处理或使用过程中也会出现σ或δ铁素体，这些相有损抗腐蚀性能和机械性能。

Annealing temperatures are confined to a narrow range toavoid σ-phase formation at lower temperature, or δ ferrite at highertemperature. 热处理温度选择范围有限，应采用较低温度以避免σ相的形成，或采用较高温度以避免δ铁素体的形成。

Recommended annealing temperatures are given in Table 1.

Rapid cooling（快速冷却）following annealing is usuallyadvisable, especially in heavy sections.

Stress-relief treatments may be used below the annealingtemperature range, but holding times should be held to a minimum to avoid ωphase and sensitization problems.

消除应力热处理温度应低于退火温度，热处理时间应考虑避免ω相的形成和敏化问题。

六、奥氏体不锈钢的光亮退火（看不懂，略）