HY 80 / 100 Steels

Diversified Metals is the largest stocking distributor of HY 80 and HY 100 steels in North America.


HY 100 Steel


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HY 100 Steel

HY 100 is a high yield steel with minimum yield strength of 100 ksi. While manysteels offer high yield strength, HY 100 also offers exceptionally high impactstrength as well. This combination makes HY 100 unique among steels. Thismaterial is used extensively in marine defense and petrochemical applications.

Diversified Metals is the largest stocking distributor of HY 80 and HY 100 in NorthAmerica; stocking a full line of round stock, while also offering gun drilled tubing.

Certified to the MIL-S-21952 C/D and T9074-BD-GIB-010/0300

HY is also available in ID/OD Tubing up to 22' length. Contact us with yourrequirements.

UNS# K32045


Diversified Metals Offers These Metal Shapes

Other (Noted Below)

Other Details / Size Requirement*
*Size, Shape, Specification & Quantity must be noted here, if it was not found in the drop-down above.

HY 100

Chemical Composition

C Mn P S Si Cr Ni Mo V Ti Cu Sb As Sn Fe
Min 0.10 0.10 - - 0.15 1.35 2.75 0.30 - - - - - - Bal
Max 0.20 0.40 0.015 0.004 0.35 1.8 3.50 0.60 0.03 0.02 0.25 0.025 0.025 0.03

Heat Analysis

HY 100 was used in the construction of the Seawolf Class nuclear powered fast attack submarines where the design dictated that the craft had to operate at greater depths than previous designs and hence withstand increased hull pressure.

In addition the alloy had to have a high degree of toughness and impact strength to withstand the massive changes in pressure and has excellent fabrication properties to allow the welding of complex structures.

The alloy has high strength, a minimum of 100ksi proof stress, which is obtained by a water quench and ageing heat treatment.

This low alloy martensitic steel contains small additions of chromium and nickel to help with corrosion resistance and is supplied in the Type B condition bright finish.

Owing to the rigorous requirements of the end application, all material is electric arc melted and vacuumed degassed with argon. All bar stock is ultrasonically tested to MIL STD 271,(NAVSEA T9074-AS-GIB-010/ 271) and has full Level I Subsea traceability.

Diversified Metals Inc also has the capabilities of supplying gun drilled tubing.

The alloy has since found wider applications in the construction of pressure vessels, armor plating, the petrochemical industry and many other applications requiring greater strength and high integrity material .


Weldments of HY-80 are noted for good ductility, notch toughness and strength. It is recommended to weld using the metal-arc process with low hydrogen electrodes of Type E-10018 or E-11018. It is important to use approved weld procedures, so that the correct heat input per inch of weld bead is introduced, which would otherwise cause degradation of notch toughness. Electrodes should be warmed before use to drive off any moisture to avoid hydrogen pick-up in the weld. Preheating is not required, except for very heavy section thickness welds or heavily constrained welds. Post-heating is not required but a stress relief anneal, after welding of sections of 1-1/2" thick or greater, is desirable. However the alloy may be used in the as- welded condition.


High pressure tubing can be made from HY 100 and HY 80 bars up to 30 feet in length. Tubes can be welded together to achieve longer lengths. The material's superior combination of ductility and fracture toughness make it a great choice for pressures as high as 14,000 PSIG operating pressure or more depending on wall thickness. The tubes have been tested up to 21,000 PSGI. Typical operating temperatures are 500o F to -20o F. The tubes can be bent up to 180 degrees with a maximum allowable thinning of 10% and flattening of 8% depending on tube OD and wall thickness and will maintain their physical properties. ID surface finishes of 64 micro or greater can be achieved. Straightness tolerances of .015" per foot can be maintained. Bars can be ultrasonically tested in immersion and/or Mag Particle tested to ensure integrity after drilling.

Fracture Toughness

High Strength HY100 steel has a well documented history in pressure vessel applications particularly in Submarine hull construction. Under arduous working conditions the steel has to have excellent low cycle fatigue properties and in conjunction with a high resistance to crack propagation. Recent work conducted by Diversified Metals Inc on 3.5” solid bar stock has confirmed the excellent fracture toughness properties of HY 100 Tests were performed to ASTM E 1820 C(T) geometry and C-R orientation at a temperature of 73ºc in air. 

Typical graph:

Initiation toughness values J1c ranged from 1341-1999 lbf-in/in
With Fracture toughness KJ1c values ranging from 210-257 ksi√2 

These were taken from bars with a range of mechanical properties 

Proof Stress UTS Modulus
ksi ksi Msi
111-115 125 -129 30
Specification UNS Number Fracture Toughness KJ1c
Modulus Msi
HY 100 K32045 201-257 30
13-8 Super Tough S13800 150 28
AerMet® 100 Aged 900ºF K92580 120 28
Hy-Tuf K32550 118 28
Ferrium® M54 K91973 115 28
250 Maraging Steel K92890 92 27
4340 G43400 70 30
300 Maraging Steel K93120 68 28

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Standards & Designations
Typical Mechanical Properties
Impact Properties
Physical Properties

Standards & Designations

Tube & Pipe
Sheet & Plate Rod & Bar Forgings
UNS K31820 MIL-S-16216 Rev K
MIL-S-24645 Rev A
MIL-S-24371 Rev B
MIL-S- 21952 Rev C & D
MIL-S-22664 Rev B
MIL-S -24512
MIL-S-23009 Rev C
Naval EB 3719 Rev C
EB 2678 Rev H
EB 3132 Rev D
ASTM A543 Grade B&C
United Kingdom
DEF STAN 02-736
Part 1
DEF STAN 02-736
Part 4
DEF STAN 02-736
Part 2

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Typical Mechanical Properties

Ultimate Tensile Strength* 0.2% Yield Strength Elong in 2" (Min) Reduction of Area (Min) Hardness
Ksi N/mm² Ksi N/mm² % % BHN
115-135 792-930 100-120 690-897 18 (L) 16 (T) 50 (L) 45 (T) 230-290

* Not a requirement of the specification
(L) longtitudinal
(T) transverse

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Impact Properties

Test Temperature Charpy V-notch Longitudinal Charpy V-notch Transverse**
°F °c ft lbs Joules ft lbs Joules
-120 -84 50 68 50 68
0 -18 70 95 60 81

**Transverse properties only required for 4" (100mm) dia or greater

The properties shown below are for guidance only and are not intended for specification purposes.

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Physical Properties

Physical Properties Imperial Units Metric Units
Density 0.28 lb/in³ 7.83 /cm³
Melting Range 2640-2750ºF 1450-1510ºc
Mean Liner Expansion 0-200ºc 18_m/m.ºc
Mean Liner Expansion 0-400 ºF 0.010 in/in/ ºF x10³
Specific Heat 0.11Btu/lb/ ºF 460J/kg ºc
Poisson€s ratio 0.28 0.28
Thermal Conductivity 48.18Btu-in/sec/ft²/ ºF 25W/m. ºk
Modulus of Elasticity 10³ 29ksi 200 N/mm²
Shear Modulus 10³ 11.2ksi 77 N/mm²

The data is believed to be accurate but Diversified Metals Inc makes no representation or warranty of any kind (expressed or implied) and assumes no responsibility with respect to its accuracy and values should only be used as a guide.

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  • Pressure vessels
  • Submarine construction
  • Naval Craft construction
  • Heavy construction equipment
  • Armor plate for vehicles
  • Bank trucks
  • Guard Booths and barriers
  • Storage tanks for liquefied hydrocarbon vapors
  • Petrochemical
  • Helicopter hold down rasters

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