Gao Fenglin: The Welder of the Rocket’s “Heart”

Great National Craftsmen program group

The reporting team of Great National Craftsmen is composed of backbone reporters in the Economic News Department and the News Channel Editorial Department of the CCTV Newsprogram Center. To discover these unknown skilled workers， they went deep into the production line， focusing on reality and life.

Great National Craftsmen

Production Team of Great National Craftsmen

New World Press

September 2019

48.00 （CNY）

Launch vehicles are the basis for human beings to enter and explore space. The engine is the heart of a launch vehicle. Gao Fenglin is a special fusion welder of the Capital Aerospace Machinery Company， the first Academy of China Aerospace Science and Technology Corporation. Engaged in welding for more than 30 years， he has shown what a “craftsman” means with exquisite skills and pursuit of perfection.

On December 2nd， 2013， Chang’e-3 Lunar Probe was successfully launched from the Xichang Satellite Launch Center. It is Long March- 3B， China’s gold medal rocket， that lifted Chang’e-3 from the earth to the moon. This rocket’s heart， the engine， was jointly welded by the welding master Gao Fenglin and his team colleagues.

Three hundred eighty thousand kilometers is the distance from the earth to the moon for Chang’e-3; 0.16 millimeters is the width of a welding spot on the rocket’s engine; 0.1 second is the allowable time error for welding. The welding craft seems easy， but in the aerospace field， the position， angle and strength of each weld requires careful thinking of the brain. In every weld， the welder’s eyesight， brain power， physical strength and willpower undergo a comprehensive test.

In China’s aerospace field， 53-year-old Gao Fenglin is the first engine welder. Now， he is challenging a new limit — welding the engine for the new generation of the Long March-5 launch vehicle developed in China.

The Long March-5 engine adopts liquid hydrogen and liquid oxygen as fuel. This is by far a rocket’s engine of hydroxide fuel with the largest thrust made by the Chinese people， and it is the key to the super carrying capacity of Long March-5. At the nozzle of the engine， the combustion of hydrogen and oxygen generates a high temperature of 3，000 degrees centigrade. There are hundreds of hollow pipelines with a diameter of several millimeters just on this nozzle. The nozzle wall is only 0.33 mm thick. The welding line is as thin as hair， and as long as two perimeters of a standard football field. Gao Fenglin needs to complete more than 30，000 precise welding operations to weave them together.

Every action must be correct and perfect， because when the engine works， the propellant at a temperature of nearly minus 200 degrees centigrade will flow into these fine pipes and cool the engine. If any welding line has a tiny flaw， the burning flame of the engine will easily tear the nozzle and thus lead to the explosion of the whole launch vehicle.

Gao Fenglin said： “We must keep an eye especially on these tiny welding lines. They will explode in the blink of an eye. If necessary， we may be required to refrain from blinking for up to ten minutes.”

The reporter asked him： “Can you keep your eyes open for ten minutes？”

“No problem， try me.”

Gao Fenglin smiled confidently.

His confidence came from his hard work when he started this career. Aerospace manufacturing requires no error. All these must start from solid basic skills. The engine， which provides power for the launch vehicle， is called the “heart” of the launch vehicle. For welding work， a tiny flaw may lead to a disaster. Therefore， for a welder， welding requires both super skills and preciseness. Gao Fenglin got this feeling from the old generation of astronauts on the first day of his work.

Chen Jifeng was Gao Fenglin’s first master and one of the first generation of explorers for special welding in New China. The special welding he engaged in is the core technology of making advanced equipment for the country. It is usually used for welding special materials which are hard and vulnerable to the environment. Mastering such an advanced welding technology requires both super skills and reverence for his career. When he accepted Gao Fenglin as an apprentice， Chen Jifeng taught him basic postures at the beginning. For example， in operation， the hands cannot lean on the workbench. He should be like a student learning to write calligraphy with his arm lifted in the air. The elbow and the wrist should be flexible so that the welding torch can touch the most difficult parts. In addition， to ensure the welding quality， the suspending hand must not be shaken at all. Another risk that affects the stability of welding is breathing. The body fluctuation caused by breathing may affect the quality of welding lines.

The reporter asked this old man in his nineties： “How do you exercise breathing？”

“You should hold your breath！”

From postures to breathing， the rigorous training was beyond Gao Fenglin’s expectation. Then something else happened， which Gao Fenglin would remember all his life.

“[At that time] When I burned a test piece， I should check the front and the back. As the test piece was hot after welding， I held it and burned my hand. Then I threw it to the ground.”

Unexpectedly， Gao Fenglin was rigorously criticized by his master for such a trivial mistake.

“My master said seriously that I should respect the object of my work.”

Respecting the object of one’s work requires a correct attitude towards work. His master’s words brought a new understanding of work to Gao Fenglin. When he was free， he would do some training. Even when he was waiting in line to buy food， he would exercise how to send welding wires with chopsticks.

It was a common action to wear a welding mask on his face. For Gao Fenglin， this was the beginning of a state of mind. Through the welding mask， he could see nothing but the workpiece flashing in the faint voltaic arc. The hard welding wire was melted into a soft fluid. At this moment， Gao Fenglin had no distractions. Nothing can disturb his mind. This was a small world he focused on for decades.

Whenever a new launch vehicle was born， it meant a technical breakthrough to Gao Fenglin. During the most difficult time， Gao Fenglin stayed in the workshop for a month rarely stopping to sleep.

In the first few nights， some masters stayed up until midnight. In the following days， only one or two masters stayed up with him until 3 o’clock in the morning. Then they said： “Gao， do it yourself.”

In this workshop of several hundred square meters， only Gao Fenglin and several welding racks were left. In the middle of the night， all he heard was the hum of the burning welding torch， and all he saw was the faint light flashing from the welding spots under the mask. It seemed that only Gao Fenglin and the dots melted by metal in front of him were left in the whole world.

About his staying up for nights， the reporter asked Gao Fenglin： “Weren’t you tired？”

“Of course I was. But driven by perseverance， I must get results. Nobody else in my family had a hair loss issue， but I did.”

With such efforts， Gao Fenglin broke through difficulties in aerospace manufacturing and welding technology one after another and became a top welding expert in the industry. Once， when an aerospace welding product was inspected by X-ray， it was suspected of having welding defects inside. Based on his understanding of the welding process and years of welding experience， Gao Fenglin believed that the welding quality was reliable and there was no problem. Finally， after strict inspection， it was proved that Gao Fenglin’s judgment was correct. This time， everyone began to spread this story， saying that Master Gao’s eyes were more accurate than X-rays.