Apparatus and method for monitoring corrosion and cracking of alloys during live well testing

A method of determining reaction of a stressable ring degradation part to downhole elements, comprising:

• a tool string, the tool string including a actuable downhole tool;
• locating the stressable ring degradation part in a tool string sub, wherein locating the stressable ring degradation part comprises placing the stressable ring degradation part in a stepped circumferential portion of an inside surface of the tool string sub;
• expressing a stress over a body of the stressable ring degradation part of up to 100% of a temperature rated yield strength for a material of the part being tested;
• locating the tool string and the sub downhole;
• actuating the downhole tool;
• removing the tool string and sub from downhole;
• removing the degradation part from the sub and making measurements of parameters of the degradation part.

A tool string sub, comprising:

• a longitudinally extending tubular housing, the housing having an outside surface and an inside surface;
• a stepped circumferential portion of the inside surface of the housing bisects the inside surface of the housing;
• a stressable ring degradation part is connected adjacent to the stepped circumferential portion of the housing;
• an inner tubular part is supported on an inner portion of the stepped circumferential portion of the housing so that the inner tubular part and the inside surface of the housing are on opposite sides of the stressable ring degradation part thereby constraining the stressable ring degradation part in a cavity defined by the inside surface of the housing, an outer surface of the inner tubular part and the stepped circumferential portion of the housing;
• and
• a moveable support member that contacts the stressable ring degradation part to express an intentional stress over a body thereof, the stress of up to 100% of a temperature rated yield strength for a material of the part being tested.