Final answer:
SAE 4130 WQT 1300 is an alloy steel with an ultimate tensile strength typically between 95 to 100 ksi after water quenching and tempering at 1300°F.
Step-by-step explanation:
The SAE 4130 WQT 1300 refers to a chromium-molybdenum alloy steel known for its strength and toughness characteristics, particularly after undergoing water quenching and tempering (WQT) at 1300°F. The term ultimate strength, often denoted as su, refers to the maximum stress that a material can withstand while being stretched or pulled before necking, which is when the specimen's cross-section starts to significantly contract. For SAE 4130 steel that is water quenched and tempered at 1300°F, the ultimate tensile strength is typically in the range of 95 to 100 ksi (kilo-pound per square inch).