Durham Police spoke to 1,676 former inmates of MedomsleyDetention Centre, near Consett, about the abusive treatment and beatings they endured from the 1960s to its closure in 1988.
The detention centre housed young inmates from across the North East.
Following a series of trials at Teesside Crown Court, it can now be reported that five former staff members have been convicted of offences including misconduct in a public office after jurors were told much of the violence was "for the enjoyment of the officers".
Judge Howard Crownson lifted reporting restrictions on the hearings after the verdicts were returned in the last of three trials.
One young prisoner was beaten up by the officer in charge of physical training when he tried to tell him that another officer - later jailed for sexual abuse - had raped him in the kitchens.
The same officer threw rocks at another prisoner causing him to fall in the gym and damage vertebrae, and another victim of a different guard was forced to remove his underwear and "bunny hop" to the showers.
Successive juries were told how a favoured device of some who worked at the centre, which housed under-21s who had been given short custodial sentences, was to ask new entries their name, and then punch or kick them when they failed to add "Sir" in their responses.
The officers involved in the abuse were brought to justice after Durham Police launched Operation Seabrook in 2013 to look into allegations relating to the the centre.
Describing the extent of the ill-treatment that some of the young men experienced, prosecutor Jamie Hill QC said: "There was an atmosphere of fear and violence throughout the institution, and, we say, that atmosphere allowed officers such as these defendants to commit offences in the knowledge that that type of behaviour was sanctioned by their colleagues.
"To simply say that it was a different time with different attitudes would be to abdicate responsibility for investigating serious allegations of crime against people made vulnerable due to their incarceration."
The seven defendants were split up into three separate trials, with five being convicted and two cleared.
A jury heard how 72-year-old Christopher Onslow was in charge of physical training at the facility between 1975 and 1985, but "exploited his position of authority in a consistently sadistic and brutal fashion".
One of his victims was climbing an obstacle course, but got stuck whilst around 20ft in the air, prompting the then-officer, nicknamed "The Machine" to throw rocks at him until he fell backwards onto the ground.
It was later discovered that the trainee had suffered three crushed vertebrae.
Onslow beat up an inmate who had been sent to work in the kitchens and was raped by Neville Husband - later convicted of sexually abusing inmates.
When the inmate said: "There's something amiss with Mr Husband in the kitchens", Onslow launched an attack and told him never to tell anyone else.
Another young offender was aged 17 when the defendant "lost control of himself" and kicked and stamped on him, before throwing medicine balls at him.
He beat up an inmate who lost a 200m race during sports day, saying he had lost a £10 bet on the 17-year-old.
Mr Hill said of Onslow: "He took advantage of the power that had been entrusted to him and abused it to an alarming degree."
He was eventually convicted by a jury of two counts of misconduct in a public office, three of assault occasioning actual bodily harm, one of inflicting grievous bodily harm, and one of wounding.
Ex-officer John McGee, 74, punched one victim who was serving a three-month sentence in the face, before forcing him to remove his underwear and "bunny-hop" to the showers after he had soiled himself.
He was found guilty of misconduct in a public office and assault occasioning actual bodily harm, while his colleague Brian Greenwell, 71, was convicted of misconduct in a public office.
Onslow, McGee and Greenwell were found not guilty of sexual offences against the young offenders.
Kevin Blakely, 67, nicknamed Broken Nose by inmates and who worked at Medomsley between 1974 and 1983, was convicted of misconduct in a public office by assaulting and abusing detainees, but cleared of causing actual bodily harm and unlawful wounding.
Alan Bramley, 70, who worked there for four years from 1973 and was dubbed Bong Eye, was convicted of misconduct in a public office by assaulting and abusing prisoners, but cleared of causing actual bodily harm and unlawful wounding.
Durham Police said that Onslow and McGee have launched appeals against their convictions.
David McClure, 63, and Neil Sowerby, 62, were cleared of all offences, including misconduct in a public office, buggery and indecent assault.
The five men are due to be sentenced at a later date.
Judge Crowson told Bramley and Blakely - the final two to be convicted - they could have bail.
He said: "I do not have any doubts about you returning, you must understand when you return, there are possibilities including prison. I will have to decide whether that is the appropriate sentence on the next occasion."