Abstract: The result of tests for various properties under both ambient and high temperatures of 15CrMo, 12Cr1MoV and 12Cr2MoWVTiB steels tempered with different periods shows that reducing the temper periods specified under the prevailing specification for high-pressure boiler pipes of the said steels will produce little influence on the metallographic structure, ambient-temperature-properties and anti-hi-temperature strength of the pipes.