Abstract: An apparatus for use in testing the bulk crush characteristics of pellet materials. The apparatus constructed such that opening and closing can be conducted without complex binding and unbinding requirements. The apparatus may be used in combination with a universal testing machine fitted with compression test plates and a load cell capable of measuring force in a vertical direction.

Abstract: An apparatus for use in testing the bulk crush characteristics of pellet materials. The apparatus constructed such that opening and closing can be conducted without complex binding and unbinding requirements. The apparatus may be used in combination with a universal testing machine fitted with compression test plates and a load cell capable of measuring force in a vertical direction.

Abstract: A stir-friction hot-working or welding arrangement uses a pin tool having a ligament 22 and a shoulder 224. The force required for incremental penetration increases markedly when the shoulder is reached. A control system for maintaining a set penetration depth includes a load cell for measuring force or pressure applied to the pin tool. The control system compares a reference signal representing the desired force with the actual force from the load cell, to produce an error signal which controls the penetration force, thereby tending to maintain a desired penetration depth. In a particular embodiment, the reference signal ramps up from a low or zero value at turn-on, to reduce forces applied upon initial penetration. In another embodiment, position signals are used to control a modulator or multiplier, which changes the error signal applied at certain positions of penetration, or at certain velocities of penetration.