التسخين المسبق HPS690W — 2.0–2.8 kJ/mm، 25–50 mm: 250–400°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.

أين يُستخدم M270M HPS690W / M270 HPS100W

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.

M270M HPS690W / M270 HPS100W عند 25–50 mm (1–2 in)

HPS690W (HPS100W) at 40–65 mm is the thickest plate commonly used with this grade. Many thickness-heat input combinations at this tier are prohibited in Table 12.8 — the fabricator must verify that the planned welding procedure matches a permitted cell before beginning production. The permitted preheat ranges narrow further, often spanning only 50°F between minimum and maximum, making continuous temperature monitoring essential.

التحكم في التسخين المسبق أدنى–أقصى لـ M270M HPS690W / M270 HPS100W

Highest-strength 690 MPa (100 ksi) bridge steel with restricted FC combinations. Table 12.8 specifies a preheat RANGE of 250–400°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.

M270M HPS690W / M270 HPS100W عند 2.0–2.8 kJ/mm

جرّب تركيبات مختلفة

استخدم حاسبة التسخين المسبق D1.5 للجسور للبحث عن أي فولاذ AASHTO M270 ومستوى هيدروجين وتركيبة مدخل حراري. انظر أيضاً حاسبة التسخين المسبق D1.1 للفولاذ الإنشائي.

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