A350 LF2 Forged Rings and F304/304L Rings Shipped to UAE

Haihao Group has completed a shipment of large forged rings for a customer in the UAE, covering two material groups: ASTM A350 LF2 Class 1 and A/SA182 F304/304L.

The order includes forged rings and forged plates in large outside diameters, with ring dimensions ranging from 839 mm to 1712 mm in the F304/304L group and from 949 mm to 1381 mm in the LF2 group. More importantly, the customer specified a detailed inspection package covering NACE requirements, ultrasonic testing, low-temperature impact performance and corrosion-related testing.

For these A350 LF2 forged rings, the manufacturing requirements went beyond dimensional control. The material condition, chemical composition, grain structure and low-temperature toughness were all part of the specification.

Two Material Grades for Different Service Requirements

The UAE order contains two distinct material groups.

The first group uses A/SA182 F304/304L, with forged rings and forged plates supplied in large dimensions. The second group uses A350 LF2 Class 1, focusing on low-temperature toughness and controlled chemical composition.

ASTM A182 covers forged or rolled alloy and stainless steel products used for pressure-system components, including flanges, fittings, valves and similar parts.

ASTM A350, meanwhile, covers forged carbon and low-alloy steel products intended for low-temperature pressure service where notch toughness is required. A350 LF2 is one of the grades used for this purpose.

This difference is reflected clearly in the inspection requirements of the order.

F304/304L Forged Rings

The stainless steel portion includes the following major dimensions:

Product	Outside Diameter	Inside Diameter	Thickness	Material
Forged Ring	1127 mm	911 mm	118 mm	A/SA182 F304/304L
Forged Ring	1198 mm	911 mm	143 mm	A/SA182 F304/304L
Forged Ring	1007 mm	759 mm	121 mm	A/SA182 F304/304L
Forged Ring	839 mm	594 mm	92 mm	A/SA182 F304/304L
Forged Ring	968 mm	759 mm	98 mm	A/SA182 F304/304L
Forged Ring	1216 mm	1063 mm	143 mm	A/SA182 F304/304L
Forged Ring	1712 mm	1521 mm	86 mm	A/SA182 F304/304L

Matching forged plates were also included at several corresponding outside diameters and thicknesses.

The customer required the stainless steel material to meet both 304 and 304L requirements, together with NACE requirements. Every applicable product was specified for 100% ultrasonic testing and 100% positive material identification (PMI), while an intergranular corrosion test using Method E was also required.

These requirements make traceability particularly important. For large stainless steel forgings, PMI provides a direct material-verification step rather than relying solely on documentation.

Why 304 and 304L Were Required Together

The dual-grade requirement is one of the more distinctive aspects of this order.

The customer specified F304/304L rather than treating F304 and F304L as separate procurement items. This requires the supplied material to satisfy the relevant requirements of both grades.

The order also called for:

NACE compliance

100% UT inspection

100% PMI

Intergranular corrosion testing by Method E

Surface finish of 3.2 μm

Positive dimensional tolerance of up to 1 mm

A350 LF2 Forged Rings for Low-Temperature Service

The second material group consists entirely of A350 LF2 Class 1 forged rings.

The supplied sizes include:

Outside Diameter	Inside Diameter	Thickness	Material
1127 mm	911 mm	118 mm	A350 LF2 Class 1
1003 mm	809 mm	76 mm	A350 LF2 Class 1
1198 mm	911 mm	143 mm	A350 LF2 Class 1
1248 mm	1013 mm	162 mm	A350 LF2 Class 1
1055 mm	860 mm	79 mm	A350 LF2 Class 1
1216 mm	1063 mm	60 mm	A350 LF2 Class 1
949 mm	759 mm	73 mm	A350 LF2 Class 1
1381 mm	1216 mm	67 mm	A350 LF2 Class 1
1321 mm	1216 mm	110 mm	A350 LF2 Class 1
969 mm	759 mm	99 mm	A350 LF2 Class 1

The customer required the A350 LF2 forged rings to undergo heat treatment while retaining the specified material grade. The order also required NACE compliance, 100% UT inspection and low-temperature impact testing.

ASTM A350 LF2 Class 1 is associated with low-temperature notch toughness requirements; the standard test temperature for a standard-size Charpy specimen is −46°C (−50°F).

For this particular order, the customer additionally specified a −50°C impact test with a minimum absorbed energy requirement of 27 J. This project-specific requirement therefore became an important part of the material acceptance criteria.

Chemical Composition Was Part of the Purchase Requirement

The LF2 material was not accepted solely on the basis of its nominal grade.

The customer’s specification also included tighter chemical composition requirements:

Carbon equivalent (CE): less than 0.42%

Carbon: less than 0.21%

Sulfur: less than 0.01%

Phosphorus: less than 0.02%

Fine grain size: Grade 6 or finer

Carbon equivalent is particularly relevant when the purchaser wants tighter control over weldability and material characteristics. ASTM A350 includes supplementary requirements addressing carbon equivalent, with lower limits capable of being agreed between purchaser and supplier.

100% UT: Looking Beyond the Surface

The large dimensions of these forgings make internal quality an important consideration.

The customer required 100% ultrasonic testing for both the LF2 and F304/304L material groups. Unlike a visual or dimensional inspection, UT is used to examine internal material conditions that may not be visible from the external surface.

For the F304/304L rings, this requirement was combined with 100% PMI. For the LF2 rings, it was combined with low-temperature impact testing, chemical composition limits and fine-grain requirements.

The resulting inspection package can be summarized as:

Material	Main Customer Requirements
A/SA182 F304/304L	NACE, 100% UT, 100% PMI, intergranular corrosion Method E, 304/304L dual compliance
ASTM A350 LF2 Class 1	NACE, 100% UT, −50°C impact, minimum 27 J, CE <0.42%, C <0.21%, S <0.01%, P <0.02%, grain size ≥ Grade 6

This is where the order differs from a standard forged-ring shipment. The acceptance criteria cover not only dimensions but also material identity, internal integrity, corrosion-related performance and low-temperature toughness.

Dimensional Control for Large Forged Rings

The largest stainless steel ring in this shipment has an outside diameter of 1712 mm, an inside diameter of 1521 mm and a thickness of 86 mm.

The largest LF2 ring reaches 1381 mm outside diameter, with an inside diameter of 1216 mm and a thickness of 67 mm.

The customer also allowed a positive dimensional tolerance of 1 mm and specified a surface finish of 3.2 μm for the applicable products.

For large forged components, these requirements need to be considered alongside the forging and heat-treatment process. A product can have the correct nominal material grade while still requiring careful control of its final dimensions and surface condition.

Haihao Group supplies large forged rings and forged plates according to customer material specifications and inspection requirements. If your project requires A350 LF2, F304/304L or other forged components with specific NACE, UT, PMI, impact or corrosion-testing requirements, send the required dimensions and inspection specification to Haihao Group for technical review and quotation.