The heat treatment of 35crmo seamless steel pipe generally adopts solution heat treatment, the so-called annealing, and the temperature range is 1040~1120℃ (Japanese standard). It can also be observed through the observation hole of the annealing furnace. The 35crmo seamless steel pipe in the annealing zone should be incandescent, but without softening and sagging.
35crmo seamless steel pipes generally use pure hydrogen as the annealing atmosphere, and the purity of the atmosphere is above 99.99%. If the other part of the atmosphere is an inert gas, the purity can also be lower, but it must not contain too much oxygen and water vapor.
Precautions for annealing 35crmo seamless steel pipe.
First, the 35crmo seamless steel tube annealing furnace should be closed and isolated from the outside air; only one exhaust port passes hydrogen as a protective gas (for igniting the hydrogen emitted). The inspection method can use soapy water to wipe the gap of each joint of the annealing furnace to see if it escapes; the sealing ring is particularly easy to wear and should be checked and replaced frequently.
Second, check the water vapor in the furnace. On the one hand, check whether the furnace body material is dry. When the furnace is installed for the first time, the furnace body material must be dry; second, whether the 35crmo seamless steel pipe entering the furnace has too much water stains. Especially if there are holes in the pipes, don't leak water, or it will ruin the atmosphere of the furnace.