440C 不锈钢
时间2009-12-23
UNS 编码

· S44004

Type Analysis /化学成份

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。

  Corrosion Resistance /抗腐蚀性能

 Stainless Type 440C resists corrosion in normal domestic environments and very mild industrial environments, including many petroleum products and organic materials. 440C能抵抗常规环境及温和的工业环境下的腐蚀，包括许多石油产品和有机物质。
This grade is used in the hardened plus tempered condition. Optimum corrosion resistance is obtained by hardening from 2000ºF (1093ºC) to ensure better carbide solution. 此种材料的状态是硬化加回火。在2000ºF (1093ºC)时硬化能促使碳更好的固溶，从而得到最好的抗腐蚀性能。
However, care should be taken to minimize time at 2000ºF (1093ºC) to avoid excessive grain coarsening. For best corrosion resistance, the tempering temperature should be below about 800ºF (427ºC). 然而，在2000ºF (1093ºC)的时间需要小心控制，以避免晶粒过度粗糙。为了最佳的抗腐蚀性能，回火温度应该在约800ºF (427ºC)以下。
For optimum corrosion resistance, surfaces must be free of scale and foreign particles and finished parts should be passivated. 为了得到最好的抗腐蚀性能，表面应无划痕和其他物质，加工完的零件需做钝化处理。

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

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