クラス 600 対クラス 900 合金鋼フランジ

技術ニュースレビュー済み: 3 8月 2026による SASA FLANGE 技術コンテンツチーム

直接の答え

クラス 900 flanges generally have heavier dimensions and a higher pressure-temperature rating than Class 600 flanges of the same material and size, but the class number is not a pressure in psi. Select the class from the applicable ASME rating table for the exact material group and design temperature, then verify dimensions, ボルト締め, 直面している, connected equipment and system loads.

重要なポイント

クラス 600 is not limited to 600 psi, とクラス 900 is not limited to 900 psi.
Material group and temperature change the available pressure rating.
Changing class affects the entire joint and may affect connected equipment.

What the pressure class designation means

ASME pressure class is a rating designation, not a direct pressure value. The allowable working pressure at a given temperature is found in the adopted standard’s pressure-temperature tables for the material group. As temperature rises, available pressure commonly falls because material strength changes.

アン ASTM A182 F22 flange and an F91 flange can have the same Class 600 designation yet require separate rating-table review. The governing piping code, design margin and any owner limits also apply.

Physical and commercial differences

Factor	クラス 600	クラス 900
Rating	Lower than Class 900 for the same material and temperature	Higher than Class 600 for the same material and temperature
ジオメトリ	Class-specific thickness, hub and bolting	Generally heavier class-specific geometry
Weight and cost	Generally lower	Generally higher due to material, machining and bolting
Interchangeability	Not assumed; mating class, 寸法, facing and equipment rating must match

The exact dimensional difference varies by NPS, flange type and standard. Use controlled tables or manufacturer drawings rather than a generic weight factor.

A five-step class selection workflow

Confirm design pressure, design temperature and upset cases.
Identify the exact material specification, grade and ASME material group.
Use the adopted ASME B16.5 or B16.47 rating table.
Check flange type, 直面している, ガスケット, bolting and the mating equipment class.
Verify external loads, cyclic duty and any project margin or derating.

Do not upgrade one flange to Class 900 without checking the mating flange, バルブ, nozzle, ガスケット, bolting and available installation space. The weakest approved component or joint condition can control the system.

What buyers should state in the RFQ

ASME standard and edition
NPS, クラス 600 または 900, and flange type
ASTM A182 grade and required condition
RF or RTJ facing, finish and gasket reference
パイプスケジュール, bore and weld-end detail
Bolting specification when supplied as a joint package
PMI, 硬度, 臨死体験, dimensional and MTC requirements

If the supplier is expected to review suitability, provide the design conditions and line-class reference. A manufacturer cannot derive the complete system design from size and class alone.

よくある質問

Does Class 600 mean 600 psi?

いいえ. It is a class designation. The permitted pressure depends on material group, temperature and the adopted ASME standard edition.

Can a Class 900 flange bolt to a Class 600 フランジ?

Do not assume compatibility. 寸法, ボルト締め, facing and ratings differ, and the joint requires engineering review.

Is Class 900 always the safer choice?

いいえ. It must be compatible with the complete system and does not correct an unsuitable material, ガスケット, bolting or weld design.

参照される主な規格

規格は発行者のページと照合してチェックされました。 3 8月 2026. 必ずプロジェクトで指定されたエディションを購入して適用してください.

合金鋼フランジの見積もりをリクエストする

材料グレードを送信します, 標準, NPS, 圧力クラス, フランジタイプ, 直面している, パイプスケジュール, 数量と検査要件. 私たちのチームは見積もりの前に技術的な説明を確認します.

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