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High Collapse Casings
Standard API 5CT and technical agreement


80T/80TT, 90T/90TT, 95T/95TT, 110T/110TT, 125T/125TT  HC Series


5.21 mm - 15.88 mm

Outer Diameter

4-1/2 inch - 13-3/8 inch

Place of Origin



High Collapse Casings

Delivery Condition

Hot Rolled, Q&T


In bundles as per customer's need

High Collapse (HC) grades exhibit higher collapse pressure than what is determined by API 5CT/ISO 11960 products.

Kunyuan Petroleum Equipment provides the High Collapse Series of proprietary steel grades for oil and gas wells where high external pressures are anticipated and collapse resistances higher than API are needed.

In addition to uniform external pressures, the reservoir can exert high pressures due to ground movements or saline strata, subjecting pipes to extreme localized external pressure.

Our mills have developed the high collapse casings such as: 80T, 90T, 95T, 110T, 125T, 80TT, 90TT, 95TT, 110TT, 125TT casings.

·Process control

1) To control strictly the inclusions in steel via the purity steel melting technology.

2) To control strictly the wall thickness and ovality of the tubes during the hot rolling.

3) To guarantee the yield strength and surface quality through the temperature and atmosphere control in the furnace during the heat treatment.

4) Through the second sizing and on line hot straightening after heat treatment, strictly control the residual stress, OD, ovality and staightness.