Manufacturing method of threaded joints for oil country tubular goods and threaded joints for oil country tubular goods

摘要

This invention provides a threaded connection for oil country tubular goods that exhibits excellent corrosion resistance and galling resistance, and a method for producing the threaded connection for oil country tubular goods. In particular, the method for producing the threaded connection for oil country tubular goods is a method for producing a threaded connection for oil country tubular goods that includes a pin (3) and a box (4). The method includes a Zn-Ni alloy plating layer formation step of forming a Zn-Ni alloy plating layer (100), and a chromate coating formation step of forming a chromate coating (200) after the Zn-Ni alloy plating layer formation step. The chromate coating formation step includes a chromate treatment step and a drying step. The chromate coating formation step satisfy one or more conditions selected from the following conditions 1 to 3.Condition 1: stirring speed of the chromating solution in the chromate treatment step: a linear speed of 0.5 m/s or more;Condition 2: chromate treatment time in the chromate treatment step: less than 50 seconds; andCondition 3: drying temperature in the drying step: 60°C or less.