UNS 编码

· S44004

Carbon 碳

0.95 to 1.2

%

Manganese (Max)锰（不超过）

1.0

%

Phosphorus (Max)磷（不超过）

0.0400

%

Sulfur (Max)硫（不超过）

0.0300

%

Silicon (Max)硅（不超过）

1.0

%

Chromium 铬

16.0 to 18.0

%

Molybdenum (Max)钼（不超过）

0.75

%

Iron 铁

Balance余量

Description/描述

 Stainless Type 440C is a high-carbon chromium steel designed to provide stainless properties with maximum hardness. It has been used primarily as a bearing steel, and is used in the hardened plus tempered condition. When heat-treated, Type 440C attains the highest hardness of any stainless steel (about Rockwell C 60). 440C含碳量高，具有不锈性能和最高的硬度。首选用途是轴承制造，是硬化加上回火状态。当热处理后，440C具有所有不锈钢中最高的硬度（约HRC60）

Applications/用途

This stainless steel principally has been used in bearing assemblies, including bearing balls and races. In addition, it should be considered for cutlery, needle valves, ball check valves, valve seats, pump parts, ball studs, bushings, and wear-resistant textile components. 首选应用是轴承结构，包括滚珠和轴套。还有，它也能用来做刀具、针形阀、球型止回阀、阀门基座、泵零件、球头螺栓、轴套、抗磨损纺织机械。

Elevated Temperature Use/高温下的使用

 Stainless Type 440C is not usually recommended for elevated temperature applications since corrosion resistance is reduced when used in the annealed condition or hardened and tempered above about 800ºF (427ºC). 通常不推荐440C用于高温环境，因为在退火或在约800ºF (427ºC)以上做硬化和回火状态下，它的抗腐蚀性能下降。

Important Note: The following 5-level rating scale is intended for comparative purposes only. Corrosion testing is recommended; factors which affect corrosion resistance include temperature, concentration, pH, impurities, aeration, velocity, crevices, deposits, metallurgical condition, stress, surface finish and dissimilar metal contact. 重要提示：以下5种酸性环境只用于比较，需做腐蚀测试；影响抗腐蚀性能的因素有温度、浓度、酸碱度、杂质、通风、速率、裂缝、沉淀物、冶炼状态、应力、表面处理和不同金属的接触等等。

Nitric Acid 硝酸

Moderate 中等

Sulfuric Acid 硫酸

Restricted限制

Phosphoric Acid 磷酸

Restricted 限制

Acetic Acid 醋酸

Restricted限制

Sodium Hydroxide 氢氧化钠

Moderate 中等

Salt Spray (NaCl)

氯化钠

Restricted限制

Humidity 湿度

Good 优秀

Specific Gravity重力

7.62

Density密度

7612

kg/m³

Mean Specific Heat平均

        0.00 °C, 100 °C

0.4602

kJ/kg/K

Mean Coefficient of Thermal Expansion平均热膨胀系数

        0.0000 °C, 100.0 °C

10.1

x 10^-6 cm/cm/°C

Thermal Conductivity导热性能

        100 °C

24.21

W/m/K

Modulus of Elasticity (E)弹性系数

200

x 10³ MPa

Electrical Resistivity电阻

        21.1 °C

600.0

micro-ohm-mm

Annealing/退火

For maximum softness, this steel should be heated uniformly to 1550/1600ºF (843/871ºC). Soak and cool very slowly in the furnace. Brinell hardness approximately 223. Intermediate or process annealing treatment-heat uniformly to 1350/1400ºF (732/760ºC). Air cool. Brinell hardness about 255. 要达到最软态，此合金须均匀加热至1550/1600ºF (843/871ºC)，均热，然后缓慢炉冷，布氏硬度大约223。中间或工序间退火处理－均匀加热至1350/1400ºF (732/760ºC)，空冷，布氏硬度大约是255。

Hardening/硬化

Heat to 1850/1950ºF (1010/1066ºC); soak; quench in warm oil or cool in air. Do not overheat. When overheated, full hardness cannot be obtained. See comments under corrosion resistance.加热至1850/1950ºF (1010/1066ºC)，均热，温油中淬火或空冷。不能过烧。过烧就不能得到最大硬度。参见“抗腐蚀”下的评述。

Tempering/回火

Hardness of approximately Rockwell C 60 will be obtained. To remove peak stresses and yet retain maximum hardness, temper at least one hour at 300/350ºF (149/177ºC). 能达到大约洛氏硬度HRC60。为了去除峰值应力和保持最大硬度，需在300/350ºF (149/177ºC)温度下回火至少一小时。

Hot Working/热作

This steel should be handled like high-speed tool steel. Preheat to 1400/1500ºF (760/816ºC), then heat slowly and uniformly to 1900/2100ºF (1038/1149ºC). Do not forge below 1700ºF (927ºC), and reheat as often as necessary. Cool in a furnace if possible or in warm dry lime or ashes. Anneal after forging; cool to room temperature before annealing.

此合金须被当作高速工具钢来处理。预热至1400/1500ºF (760/816ºC)，然后缓慢并均匀加热至1900/2100ºF (1038/1149ºC)。不能在1700ºF (927ºC)以下锻造，尽量减少重复加热次数。如果可能要炉冷或在温热干燥石灰或粉尘中冷却。锻造后的退火：退火前需冷却至室温。

Cold Working/冷作

If annealed for maximum softness, this steel can be moderately cold formed or headed.

如退火得到最软态，此合金能被适当的冷塑或冷镦。

Machinability切削性

For most machining operations, this steel cuts best when in the dead soft annealed condition. Because of its high carbon content it machines somewhat like high-speed steel. Because chips are tough and stringy, chip curlers and breakers are important. 为了方便切削加工，此合金在软态退火时最易切割。因其含碳量高，切削起来与高速钢有些相似。因碎屑坚硬而连续，配套的卷屑机和断裂机就很重要。
The following are typical feeds and speeds for  Stainless Type 440C. 下列是此合金典型的送料和加工速度表。

Additional Machinability Notes/切削性能附件说明

When using carbide tools, surface speed feet/minute (SFPM) can be increased between 2 and 3 times over the high speed suggestions. Feeds can be increased between 50 and 100%. 当使用碳素工具时，表面速度（表面速度/秒）能增加至上表中高速部分（HIGH SPEED）的2－3倍。送料速度能提高50％－100％。
Figures used for all metal removal operations covered are average. On certain work, the nature of the part may require adjustment of speeds and feeds. Each job has to be developed for best production results with optimum tool life. Speeds or feeds should be increased or decreased in small steps. 上表数据均是标准值，具体的加工中可能需要调整速度和送料。每项工作都以最好的加工和保护刀具的使用为目标，速度和送料都可能有少许调整。

Grinding and Polishing/抛光和打磨

In cutlery applications, grinding and polishing are very important.  Stainless Steel Type 440C works well in these operations but considerable care must be used not to overheat since both the hardness and corrosion resistance may be lowered. 生产刀具时，抛光和打磨就非常重要。此合金都能很好的接受这些加工。但是请谨慎注意，不能过烧，因为过烧会使硬度和抗腐蚀性能下降。

Weldability/焊接

Because of its high-hardness capability, this steel is seldom welded. However, if welding is necessary, the parts should be preheated and maintained at about 500ºF (260ºC), welded, and then immediately given a 6-8 hour anneal at 1350/1400ºF (732/760ºC) with a slow furnace cool. The parts should not be allowed to cool below 500ºF (260°C) between welding and annealing. High welding heat inputs should be used. To obtain mechanical properties in the weld similar to those in the base metal, welding consumables of like composition should be considered. Otherwise, AWS E/ER309 might also be considered. 因其具高硬度能力，此合金很少被焊接。然而，如果有必要，部件需预热并保持在500ºF (260ºC)左右，焊接，然后立即在1350/1400ºF (732/760ºC)下进行6－8小时的退火并缓慢炉冷。部件在焊接和退火过程中不能冷却低于500ºF (260°C)。焊接时需保持高温。为了使合金的机械性能在焊接后与焊接前的相似，应该考虑使用与焊接消耗类似的焊剂。否则就应该考虑AWS E/ER309。

Note: While this material meets the following specifications, it may be capable of meeting or being manufactured to meet other general and customer-specific specifications. 本材料除满足下列标准外，还可以按照其他通用和客户指定的标准生产。

·  AMS 5618

·  AMS 5630

·  AMS 5880

·  ASTM A276

·  ASTM A314

·  ASTM A473

·  ASTM A493

·  ASTM A580

·  ASTM A756

·  QQ-S-763

·  Wire

·  Wire-Rod

·  Bar-Rounds

·  Billet