API 2MT1

API 2MT1 Structural Steel

Carbon-Manganese Steel Plate with Improved Toughness

General Product Description

API 2MT1 is an intermediate-strength structural steel plate used in the welded construction of offshore structures. API 2MT1 has a minimum yield strength

of 345 MPa [50 ksi] and a minimum transverse Charpy V-notch impact toughness of 41J [ 30 ft-lbf ] at -18°C [ 0°F ].

Applications: API 2MT1 is intended primarily for use in offshore structures for Class “B” applications as defined in API RP 2A. API 2MT1 steel plates are suitable for

use in select portions of offshore structures which must resist impact and plastic fatigue loading but are not subjected to substantial through-thickness (Z-direction) stresses.

Dimensions: The following API 2MT1 plate sizes are available:

Thickness: 12.7 mm– 50.8 mm (0.500”– 2.000”);inquire >50.8 mm to 63.6 mm (2” to 2.5”)

Width: 1,829 mm - 3,124 mm (72” - 123”)

Length: 6,100mm – 27,430mm (240” - 1080”)

Mechanical Properties

Tensile Testing is performed transverse direction according to ASTM A6 and A370 requirements.

The minimum values are tabulated below:

Thickness, t mm [in.]	0.2% YS MPa [ksi], min.	UTS MPa [ksi]	Elongation in 50 mm [2”], min. %	Elongation in 200 mm [8”], min. %
t≤63.5 [2.50”]	345 [50]	448-620 [65 to 90]	23	18

Charpy V-Notch Impact Testing is performed using transverse specimens in accordance with ASTM A370 and ASTM A673 Frequency (H).

Specimen Size, mm	Specimen Size in.	Minimum Average Energy J [ft-lb]	Minimum Single Value Energy J  [ft-lb]	Test Temperature °C [°F]
10 x 10	0.394 x 0.394	41 [30]	34 [25]	-18 [ 0 ]

Chemical Composition (Heat analysis, wt %, max. unless indicated)

C	Mn	P	S	Si	Al, Total	Nb	Ti1	V1	N2	B2	Zr3	Ce3
0.12	1.15- 1.60	0.030	0.010	0.10- 0.40	0.020- 0.060	0.010- 0.040	0.020	0.080	0.012	0.0005		0.010

1. Minimum value, if any, shall be as agreed upon and stated on the order.

2. Shall not be intentionally added.

3. Shall not be intentionally added without specific approval of purchaser. Analysis of Ce not required if not added.

Thickness, t mm [in.]	CEIIW Max	Pcm Max	CEIIW Typical	Pcm Typical
≤ 50.8 [2”]	0.43	0.24	0.39	0.17
50.8< t ≤ 63.5 [2” < t  ≤ 2.5”]	0.45	0.25	na	na

CE_IIW = C+Mn/6+(Cr+Mo+V)/5+(Ni+cu)/15

Pcm = C+(Si/30)+(Mn+Cu+Cr)/20+(Ni/60)+(Mo/15)+(V/10)+5(B)

Tolerances

Thickness, width, and length tolerances for API 2MT1 steel plate are in accordance with the requirements

of ASTM A6. The flatness tolerance for as-supplied product is ½ ASTM A6.

Delivery Condition

API 2MT1 steel plate is supplied in the as-rolled (hot rolled or controlled rolled) or TMCP condition.

Fabrication and Other Recommendations

Weldability: Welding of API 2MT1 shall be performed in accordance with the applicable welding code.

In the absence of a specified welding code, the following suggested minimum preheat and interpass

temperatures and welding consumables are provided. Special welding consumables and welding

procedures may be required to match the base metal toughness. Low hydrogen practices are strongly

recommended, including the removal of surface moisture.

Welding Process	Thickness, mm [in]	Minimum Preheat and Interpass Temperature	Consumables
Shielded Metal Arc (SMAW)	Up to 38.1 [1.5”]	10°C [50°F]	AWS E7015-X, E7016-X, E7018-X
	>38.1 [1.5”] to 63.5 [2.5”]	65°C [150°F]
Gas Metal Arc (GMAW)	Up to 38.1 [1.5”]	10°C [50°F]	AWS ER70S-X
	>38.1 [1.5”] to 63.5 [2.5”]	65°C [150°F]
Submerged Arc (SAW)	Up to 38.1 [1.5”]	10°C [50°F]	AWS F7XX-EXXX-XX
	>38.1 [1.5”] to 63.5 [2.5”]	65°C [150°F]
Flux Cored Arc (FCAW)	Up to 38.1 [1.5”]	10°C [50°F]	AWS E7XTX-X
	>38.1 [1.5”] to 63.5 [2.5”]	65°C [150°F]

Supplementary Requirements

By agreement between the purchaser and plate manufacturer, the following Supplementary Requirements may be

specified on the purchase order: S1 (Ultrasonic Examination),

S9 (Simulation of Post-Weld Heat Treatment), S13 (Surface Quality), S14 (Thickness Tolerance) and S15 (Manufacturing

Procedure Specification [MPS]).