API 2Y Gr50

API 2Y Grade50  Quenched and Tempered Steel Plate

Nearest Equivalent Grade : EN10225 S460G1+Q, S460G2+Q, BS7191:1989  450EM, 450EMZ

Characteristic :

API 2Y Grade50 is High Strength Structural Steel Plate, for welded construction of offshore structures/offshore platforms in

selected critical portions which must resist impact, plastic fatigue loading, and lamellar tearing.

API 2YGrade 50 has a yield strength of 344-517MPa (50-75ksi) and min tensile strength 448MPa (65ksi)

for steel plates thickness ≤ 25.4 (1”). Yield strength of 414-482MPa (50-70ksi) and min tensile strength 448MPa (65ksi)for

steel plates thickness ≥ 25.4mm (1”) to 150mm (6”) and both transverse Charphy V-notch impact toughness of 41J (30 ft-lbf) at -40ºC (-40ºF).

API 2Y Gr50 is an offshore steel grade which is regulated by American Petroleum Institute (API) and

in some cases certified by the American Bureau of Shipbuilding (ABS).

Delivery Condition : Roller Quenched and Tempered (RTQ)

API 2Y Grade50 high strength steel plates are delivered in the Roller Quenched and Tempered (RQT) condition.

Roller Quenched and Tempered steel plates are produced by heating high quality reversing  plates of the require chemical composition and

thickness rolled from continuously cast slabs or direct rolled ignots of sulphur steel. The plates are heated to a temperature, depending on grade,

in the range 880°C to 930°C and then water quenched using a Drever Roller Pressure Quench unit.

The plates are quenched at very high cooling rates by large volumes of high pressure water sprayed across the full width

of the plate on to both top and bottom surfaces. During the quenching operation the plates are held flat and are in continuous motion,

thus ensuring that each part of the plate is cooled at the same rate. The precise rate of cooling during quenching is achieved by controlling

the water pressure and the speed of passage of the plate through the unit, allowing consistent

properties to be achieved in the final product. The quenching efficiency of this process is extremely high,

giving the desired properties with very low levels of microalloying elements and low levels of CEV.

The final levels of strength and toughness are achieved by tempering heat treatments performed in furnaces with uniform

temperature distribution and close temperature control. Using this method, plates satisfying grades requiring nominal yields of 420 MPa,

450 MPa and 460 MPa can all be produced from steel slab or ingots of similar target compositions.

Thickness, t mm [in.]	Yield Strength MPa [ksi]	Tensile Strength min MPa [ksi]	Minimum Elongation (in 2”) / %	Minimum Average Charpy-V Impact Energy / J @ -40ºC
t ≤ 25.4 [ 1.00” ]	344-517 [ 50 - 75 ]	448 [ 65 ]	22	41
t 25.4 - 152mm [1.00” ] - [ 6.00” ]	414-482 [ 50 - 70 ]	448  [ 65 ]

Chemical Composition (%) Unless a range is specified, individual values are maximum

C max.	Si	Mn	S max.	P max.	Cr. max.	Mo max.	Cb max.	Cu max.	Ti	Ni max.	Al(tot)	N max
0.16	0.15/0.50	1.15/1.60	0.01	0.03	0.25	0.08	0.03	0.35	0.003/0.02	0.75	0.02/0.06	0.012

CE 0.39 to 38.1mm (1½”)

CE 0.41 to  88.9mm (3½”)

CE 0.43 to 152.4mm (6”)

TCVN Require

Testing

A full range of testing facilities are available within our steel mill at which the standard testing requirements of each specification are undertaken.

Further specialist testing can be undertaken as necessary at one of the steel mill technology centers.

Non-destructive testing (NDT) facilities are available in- house. When specified, testing is carried out by NDT operators who are certified in accordance with EN473.

The NDT facility can be incorporated into the 100% inspection process, an offline activity for checking the product conformity to the standard applied.

This inspection service is operated in a dedicated bay by teams of experienced steel inspectors ensuring a high level of service and a quality product.

Certification

Mill certification is in accordance with EN10204. Inspection certificates are normally supplied to Type 3.1.B although at the customer’s request other

certification can be supplied, e.g. Types 3.1.C, 3.2 and 3.1.A. Certificates are available in English, French and German.

Shearing

API 2Y Gr50 high strength steel plates can be cold sheared. In view of the high strength level relative to mild steel and other structural steels,

proportionately higher shearing power is required for any given thickness.

Flame cutting

Plates may be cut satisfactorily with standard oxy-gas equipment. Neither preheating nor postheating is normally required.

However, where fabrication codes specify maximum hardness levels, attention must be paid to the selection of appropriate gas cutting procedures.

Care should be taken to ensure that flame cut edges are free from sharp notches, as these may prove detrimental to subsequent cold forming operations.

Prior to cold forming, gas cut edges should be ground back in regions to be bent.

In multiple cutting situations, care is required to achieve a balanced arrangement of the cutting torches to minimize plate distortion.

Many fabrication standards stipulate that cut edges not fully incorporated into a weld should be ground back to remove the hard edge.

It is recommended that these standards are followed.

Plasma Cutting

Plates may be plasma cut within the operating thickness ranges of the equipment. All plasma cut edges which form part of a weld preparation

should be incorporated fully into the weld. As with flame cut edges, plasma cut edges should be ground back in the regions to be bent prior to cold forming.

Cold forming

All types of structural steel plate described in this brochure can be readily cold formed. Due to the higher strength level of API 2Y Gr50 steels,

the power required for cold forming is proportionately greater than that required for mild steel plates of the same thickness. For the same reason,

greater spring-back will be experienced for which due allowance must be made.

Bending and brake press forming of API 2Y Gr50 steels should, where possible, be carried out with the axis of bending at right angles to the rolling direction.

Minimum values of bending radius and of die opening for 90° bends, expressed as multiples of the plate thickness (t), are given in the following table.

Bend axis vs. rolling direction	Minimum inside bending radius	Minimum die opening
Perpendicular	3.0t	8.5t
Parallel	4.0t	10.0t

Hot Forming

API 2Y Gr50 Quenched and Tempered high strength steels are not suitable for hot forming. Should it be necessary to consider a warm forming

operation or a line heating operation, it should be performed at a temperature below 550°C and at least 50°C below the tempering temperature

stated on the inspection certificate. Total heating times for single or multiple forming operations should be restricted to less than 1 hour per 25mm of plate thickness.