Project "Granit" was never merely an engineering solution; it was a twenty-ton monument of metal and pressure, birthed from the suffocating grip of famine and industrial paralysis. Viktor Mikhailovich Kovalenko, an engineer at the Putilov plant forced to labor in the depths of the Urals, constructed this system not out of luxury, but driven by the desperate necessity to fuse the remnants of a shattered empire. In 1923, within Sverdlovsk, under the constant surveillance of the Cheka and amidst a chronic scarcity of raw materials, he coupled a Burmeister & Wain marine compressor with a radical abrasive-flow technology, aiming to transform armor plating into the piping that no remaining rolling mill could produce.
The system’s primary component, the GR-1 cutting head, was an engineering marvel with a throat diameter of 4.7 millimeters, machined from a solid block of tungsten-molybdenum alloy. Through this aperture, a mixture of air and aluminum oxide was propelled at a pressure of 8.5 megapascals, reaching a velocity of 612 meters per second. This was no conventional cutting; it was a kinetic force that simultaneously heated the metal to its yield point and deformed it. When 35-millimeter-thick Krupp steel armor collided with particles traveling at 480 meters per second, physics dictated a ruthless condition: either a precise standoff distance of 18 millimeters or catastrophic erosion.
Kovalenko’s choice to use natural vulcanized rubber as a protective sleeve over the 508-millimeter-diameter forming mandrel was the system’s weakest, yet most essential, link. Each ten-meter pipe required the replacement of this 2-millimeter-thick sleeve, as rebounding abrasive grains would reduce the steel rod to a pitted, uneven surface within minutes. It was a human-engineered technological attrition, designed to shield a far more precious apparatus from the inevitable physical chaos induced by a flow moving at Mach 2.4.
The internal matrix, composed of fine aluminum oxide particles, acted as a fluid wedge; as the plate moved at a rate of 0.8 meters per minute, a radial pressure of 0.8 megapascals forced the cold, rigid steel to bend around the OF-1 mandrel. Without the use of any auxiliary heating, all energy was derived from friction and kinetic impact, ensuring the process compromised the crystalline structure only to a depth of 0.2 millimeters, leaving the remaining mass of metal in an unaltered thermal state—a stark contrast to traditional rolling, which often degrades the structural integrity of the reinforcement.
An unexpected turn occurred when the local Sverdlovsk party leadership, witnessing "Granit’s" ability to perforate steel with extreme precision, ordered the device reoriented from pipe production to "special marking tasks." The machine became a mandatory instrument for stamping identification numbers onto confiscated property, as traditional hardened-steel dies would shatter upon striking the low-quality, impurity-laden metal. Kovalenko, unwilling to let his creation become a tool of repression, deliberately calibrated the nozzle to leave blurred, nearly illegible impressions.
This sabotage became an open secret, and the engineer spent hundreds of hours tuning the airflow, striving only to keep the device "functional but ineffective." The noise, reaching 130 decibels, became his shield; factory overseers avoided the workshop, where the sound vibrated the very internal organs of those nearby. Kovalenko successfully feigned technical malfunctions by using an excessive volume of aluminum oxide, which would rapidly clog the supply channels, halting operations for lengthy cleaning cycles.
The system’s ultimate fate was determined not by technical failure, but by a bureaucratic audit, which concluded that "Granit" consumed more compressed air than the rest of the factory line combined. The heads of the compressor station complained of constant pressure drops that disrupted the operation of nearby machine tools. When the management of the Uralmash plant decided to optimize energy consumption on December 12, 1927, "Granit" became the first target slated for removal from the production cycle.
On December 12, 1927, after the Uralmash plant management officially terminated funding for "Granit" and disbanded the creative team, fourteen engineers and twenty-two technical staff were reassigned to standard machine maintenance departments, and the entire apparatus was scrapped for metal, leaving future generations with only a single operational logbook as a silent testament to a lost vision.