1.1This practice covers the evaluation of residual stresses in extruded profile or molded SP parts. The presence and relative magnitude of residual stresses are indicated by the crazing of the specimen part upon immersion in one or more of a series of chemical reagents. The specified chemical reagents were previously calibrated by use of Environmental Stress Cracking (ESC) techniques to cause crazing in sulfone plastics (SP) at specified stress levels.

1.2This practice applies only to unfilled injection molding and extrusion grade materials of high molecular weight as indicated by the following melt flow rates: PSU 9 g/10 min, max., PESU 30 g/10 m, max, and PPSU 25 g/10 min, max. Lower molecular weight (higher melt flow) materials will craze at lower stress levels than indicated in Tables 1-3. (See Specification D6394 for melt flow rate conditions.)

Mixture	Mixture Composition		Critical Stress, MPa (psi)
Mixture	% by volume Ethanol	% by volume Ethyl Acetate	Critical Stress, MPa (psi)
1	50	50	15.2 (2200)
2	43	57	12.1 (1750)
3	37	63	9.0 (1300)
4	25	75	5.5 (800)

Mixture	Mixture Composition		Critical Stress, MPa (psi)
Mixture	% by volume Ethanol	% by volume MEK	Critical Stress, MPa (psi)
1	50	50	17.9 (2600)
2	40	60	10.3 (1500)
3	20	80	6.9 (1000)
4	0	100	5.9 (850)

Mixture	Mixture Composition		Critical Stress, MPa (psi)
Mixture	% by volume Ethanol	% by volume MEK	Critical Stress, MPa (psi)
1	50	50	22.8 (3300)
2	25	75	13.8 (2000)
3	10	90	9.0 (1300)
4	0	100	8.0 (1150)