The contest required participants to work with precious metals, using techniques like filing, hollowing, sawing, and welding to process and repair jewelry components within a set period of time.
Zhang was up against contestants from more than a dozen countries, and stood out for being the only one to pull off all the tasks with all four modules.
Every step demanded exceptional accuracy and skill, a test not only of the participants' technical abilities, but also of their proficiency at shaping, welding, and controlling the metals.
The young man's success was a breakthrough for China in this category.
"The theme for the hairpin was announced on the spot, and we had to complete a different assignment given to us every day for four days," Zhang says.
The competitors had to come up with a design, explain its meaning, and draw a draft.
"There was a module that tested originality, and I fashioned three different petals and inserted them at different positions along the hairpin to symbolize the early, middle and late stages of life," he says.
At the same time, traditional crafting techniques, like welding and piercing, were used to bring everything together.
The prize has given Zhang a shot of confidence.
He was one of the 68 Chinese contestants who competed in all 59 skill discipline categories, taking home 36 gold, nine silver, and four bronze medals, along with eight medallions for excellence.
Shawna Bourke, director of marketing and communications at WorldSkills International, spoke highly of China's systematic approach to developing skilled talent, and added that the country has used the World-Skills Occupational Standards to skill up millions of young people.
Originally from Hengshui city in Hebei province, Zhang enrolled at the Beijing Arts and Design Technology Institute in 2017 after graduating from middle school.
Still just a youngster, he didn't have a clear plan for his future, and says he was acting like a naughty boy, doing the bare minimum at the institute.
It wasn't until the following year, when he had to choose a major, that he turned over a new leaf after being stunned as he watched his seniors fashion delicate and sparkly jewelry with their bare hands.
The drafting and hands-on crafting process of working with precious metals piqued his interest and led him to opt for jewelry design, but as he'd previously been remiss about studying, he didn't get off to a good start.
Forced to knuckle down, Zhang developed his drawing and crafting skills from scratch.
"I don't even remember how many sheets of paper I used, how many pens I wore out, or how many failed pieces I made," he says.
His diligence finally woke his innate talent, enabling him to quickly master indispensable skills and get them down to a fine art.
When the school was selecting candidates for the national training center for the WorldSkills Competition in jewelry making later in 2018, his instructor, Zhao Kaiyue, signed him up.