예열 M270M HPS690W — 2.0–2.8 kJ/mm, > 50 mm: 300–450°F

M270M HPS690W / M270 HPS100W

AASHTO M270M HPS690W (M270 HPS100W) is the highest-strength bridge steel at 690 MPa (100 ksi) yield, reserved for the most demanding long-span and cable-stayed bridge applications. It follows a completely different FC preheat table (Table 12.8) with min-max ranges and many prohibited thickness-heat input combinations marked with “—”. Table 12.8 requires H4 or H8 designated consumables; H16 is not permitted. NFC preheat per Table 6.3 Group 2; maximum interpass per Table 6.4 is 205°C (400°F) for material up to 40 mm, 230°C (450°F) above.

M270M HPS690W / M270 HPS100W이 사용되는 곳

Reserved for the most demanding long-span and cable-stayed bridge applications where maximum weight reduction justifies the material cost premium and fabrication complexity. Table 12.8 imposes both minimum AND maximum preheat limits, and many thickness-heat input combinations are outright prohibited. Fabricators must plan weld procedures around the permitted combinations before cutting plate. Filler metals must carry the H4 or H8 supplemental designator — H16 is not permitted for HPS690W FC applications.

> 50 mm (> 2 in)에서의 M270M HPS690W / M270 HPS100W

HPS690W (HPS100W) above 65 mm pushes the boundary of what can be reliably welded in FC bridge service. Most heat input combinations are prohibited at this thickness, leaving only narrow windows where welding is possible. Production planning must account for weather, ambient temperature, and wind conditions that could push joint temperature outside the narrow permitted range. Pre-production mockup testing per D1.5 Clause 12 is advisable.

M270M HPS690W / M270 HPS100W의 최소–최대 예열 제어

Highest-strength 690 MPa (100 ksi) bridge steel with restricted FC combinations. Table 12.8 specifies a preheat RANGE of 300–450°F for this thickness and heat input combination. Unlike other FC grades, HPS690W requires both minimum AND maximum preheat control because the Q&T microstructure is sensitive to both excessive and insufficient heat. Many thickness-heat input combinations are prohibited ("—" in the table) because no safe preheat window exists — the steel cannot be reliably welded under those conditions.

2.0–2.8 kJ/mm에서의 M270M HPS690W / M270 HPS100W

다양한 조합 시도

D1.5 교량 예열 계산기를 사용하여 AASHTO M270 강재, 수소 수준 및 입열량 조합을 조회하세요. D1.1 예열 계산기도 참조하세요.

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