Atlas Grade datasheet 630 rev May 2008 July 2010

1 Grade Data Sheet630 (17-4PH)Revised January 2008 Page 1 of 630martensitic precipitation hardeningstainless steel has a combination of highhardness and strength after suitable heattreatment. It also has similar corrosion andheat resistance to Grade 304. The terms "Type630" and "17-4PH" refer to the same great benefit of this Grade (and of otherprecipitation hardening grades of stainlesssteel) is that they are generally supplied in thesolution treated condition, in which they arejust machinable, and then can be age hardenedto achieve quite high strengths.

2 This agingtreatment is so low in temperature that there isno significant distortion. These grades aretherefore well suited to production of longshafts, which require no re-straightening afterheat ResistanceGood resistance to a wide range of corrosiveenvironments; approaching that of Grade 304stainless steel. Like 304, this Grade is subjectto pitting and crevice corrosion in warmchloride environments. Grade 630 has beenused for boat shafting for fresh water, and insea water with the addition of resistant to stress corrosion cracking ifaged at 550 C or higher.

3 Higher agingtemperatures give better SCC 630 is resistant to sulphide stresscracking (SSC) if highly aged; NACE MR0175permits the use of 630 but only in a double agehardened condition (refer to MR0175 and ASTMA564M).In solution treated Condition A the Grade haslower resistance to stress corrosion cracking,andlowerductilitycomparedtoaged conditions. It should not generally be used inthe solution treated condition, even if thehardness is considered Atlas Technical Assistance for specificenvironmental ResistanceThis Grade has good oxidation resistance, butto avoid reduction of its mechanical propertiesand hardness it should not be used above in the range 370-480 C should beavoided if ambient temperature toughness TreatmentSolution treatment (Condition A)Heat at 1040 C for hour and cool to 30 Cmaximum in air.

4 Oil quenching may be used forsmall non-intricate (Aging)Aftersolutiontreatmentasinglelowt emperature "age hardening" treatment isemployed to achieve required properties, asbelow. This treatment results in no distortionand only superficial discolouration. A slightdecrease in size (shrinkage) takes place duringthe hardening; this is approximately forCondition H900 and for mechanical properties achieved aftersolution treating and then age hardening at theindicated temperatures are as in the table inthe following page.

5 The Condition is designatedby the age hardening temperature in F(Condition A is solution treated, ie not aged).WeldingGrade 630 can be successfully welded by allstandard methods. Preheating is not comparable to those of the parentmetal may be achieved in the weld metal bypost-weld heat treatment. As for other highstrength steels precaution should be taken indesign and welding procedures to avoidconcentration of weldment steel is usually supplied in the solutiontreated condition, in which it can be is similar to Grade ApplicationsGears, bolts and valve components.

6 Plasticmoulding dies. High strength pump shafts andboat propeller shafts. Engine components. Ingeneral applications where some level ofcorrosion resistance is needed in conjunctionwith high strength or Data Sheet630 (17-4PH)Revised January 2008 Page 2 of PropertiesThese properties are specified for bar products in ASTM A564/A564M; round bar is the mostcommonly available product form for this Grade . Similar but not necessarily identical propertiesare specified for other products such as plate and forgings in their respective Specification (%)GradeCMnSiPSCrNiCuNb+ Property SpecificationHardeningHardnessConditionT emp( C)Time(h)TensileStrength(MPa) Proof(MPa)Elongation(% in50mm)Rockwell C(HR C)Brinell(HB)

7 A--1105 max363 maxH9004801131011701040388H9254954117010 701038375H10255504107010001235331H107558 0410008601332311H110059549657951431302H1 15062049307251628277 Single property values are minima except as noted as typical or from ASTM A564M; these values apply only to certain size ranges. The specification should beconsulted for the complete details of these properties and of heat treatment treatment is at 1040 C followed by cooling as double-aging treatments H1150M and H1150D are also possible refer to ASTM Properties(typical values in the annealed condition)Mean Coefficient of ThermalExpansionThermalConductivityGrade Density(kg/m3)ElasticModulus(GPa)0-100 C( m/m/ C)0-315 C( m/m/ C)0-538 C( m/m/ C)at 100 C( )at 500 C( )SpecificHeat0-100 C( )ElectricalResistivity(n.)

8 M) Specification 630 These comparisons are approximate only. The list is intended as a comparison of functionally similarmaterialsnotas a schedule of contractual equivalents. If exact equivalents are needed originalspecifications must be Alternative GradesGradeWhy it might be chosen instead of 630 (17-4PH)431431 has higher toughness than 630. Better availability in some machining martensitic stainless steel - better machinability. Lower cost but lower corrosion resistance of 316 is needed, but with much lower strength than better corrosion resistance than 630, with a lower strength (but not as low as 316).

9 Limitation of LiabilityThe information contained in this datasheet is not an exhaustive statement of all relevant information. It is a generalguide for customers to the products and services available from Atlas Steels and no representation is made or warrantygiven in relation to this document or the products or processes it describes.