Simultaneous travel: City, infinite evolution

Chapter 266 Northern Expedition against the Xiongnu (Part 1)

The inner layer of the furnace is made of a mixture of quartz sand and clay, which can withstand a high temperature of 1500℃.

The outer layer is reinforced with rammed earth, more than 20cm thick, to reduce heat loss.

The blower system adopts a dual-nozzle design, with ceramic air ducts inserted symmetrically on both sides, with an inner diameter of 8-10cm.

The power source uses a water-driven bellows, eliminating the need for manual blowing and increasing efficiency by 3 times.

The preheating device uses air ducts to preheat the furnace wall to 300°C, thereby increasing the temperature of the air entering the furnace.

To prevent carbon monoxide poisoning, Chen Hong also built a tall chimney that was more than twice the height of the furnace to force lateral ventilation.

After the furnace was built, the steelmaking stage began.

The first step is preheating.

Pour in coke, fill the furnace chamber, and blow air for 30 minutes until the furnace walls turn white.

The temperature is controlled at 1100℃ when the flame inside the furnace turns bright yellow.

The second step is to feed the materials.

Adding cast iron sheets (≤2cm thick) or scrap iron products, along with 200g of limestone per kilogram of iron to aid melting, can reduce impurities.

The furnace temperature is controlled at 1200℃ when the iron melts into an orange-red slurry.

The third step is roasting and refining.

Stir the clay rapidly inside the furnace with a long iron rod; sparks flying indicate normal decarburization.

The furnace temperature has been controlled at 1300℃ until the slurry thickens and becomes honeycomb-like.

The final step is carbon control.

Stir-fry until the iron ball emits a blue light, then stop the heat to obtain "low-carbon steel".

By retaining a small amount of molten iron, "high-carbon steel" is obtained.

Generally, a silvery-white grain on the fracture surface is preferred.

If the carbon content is too low, you can sprinkle in 0.5% coke powder to increase the carbon content.

The final steel, before being forged into weapons, must be hammered by a blacksmith.

While still hot, repeatedly pound with an iron hammer to squeeze out silicate impurities, with a loss rate of about 31%.

After being folded and forged 10 times (1024 layers), it can reach the standard of "thirty steelmaking" in the Han Dynasty.

Although steel produced by the frying process has uneven carbon distribution and more inclusions, its quality is not as good as that produced by the crucible process.

But its biggest advantage is that the raw materials are cheap and its mass production capacity is extremely strong.

It can mass-produce iron farm tools and weapons.

Even the worst steel is still better than the bronze that's the mainstream material of this era.

Iron weapons forged using the hot-frying method can crush easily chipped bronze weapons, and their toughness can also crush brittle bronze weapons.

The cost was much lower than that of bronze, and the output was many times higher.

Moreover, the Xiongnu and Baiyue barbarians of the grasslands couldn't even gather enough bronze artifacts.

Iron weapons forged using the hot-frying method are more than enough to crush these guys.

To enhance the power of the weapons, Chen Hong optimized the quenching method.

Quenching with 10% salt water increased the hardness to the level of Tang Dynasty horizontal swords.

However, if we don't pursue hardness but rather toughness, such as the elasticity required for springs.

Using a two-liquid quenching process, first water and then tung oil, can improve toughness by 30%.

If the goal was to develop high-end weaponry, Chen Hong employed an alloy method.

Adding 10% pyrolusite increases impact resistance by 200%, resulting in manganese steel.

Adding 5% chromite increases corrosion resistance by 150%, making it less prone to rust.

With Chen Hong's technical support, Daqin frantically built steelmaking furnaces, with tall chimneys billowing black smoke, refining steel day and night.

The output of this underground jar furnace is 50 kg/batch, and the production cycle is 6 hours per furnace.

However, the lifespan of a refractory furnace is only 10-15 heats, so Chen Hong always has a refractory material maintenance team on hand.

Regularly apply new refractory mortar to the inner wall of the furnace and replace the inner layer of quartz sand and clay mixture.

Currently, Daqin has built a total of 300 steelmaking furnaces in this steel plant.

Apart from necessary maintenance, the furnace operates almost continuously day and night, with steelmaking taking turns to rest.

The average daily steel production can reach about 45 tons.

This output is already incredibly impressive in the Qin Dynasty.

This was enough to allow the Qin army to completely re-equip itself, upgrading from simple guns to powerful cannons.

Moreover, steelmaking furnaces are constantly being built and expanded, with steelmaking furnaces being built in more places and iron ore being mined for steelmaking.

As time goes by, the stockpile of steel continues to grow.

Countless blacksmiths hammered and forged all kinds of weapons, armor, and arrows.

Chen Hong upgraded the assembly line equipment workshop production system based on the Daqin military industry system.

To achieve standardized production of weapons, armor, and arrows, and to implement assembly line production.

This greatly increased the production of military weapons, enhanced the combat effectiveness of the Qin army, and improved combat efficiency.

One by one, the soldiers replaced their bronze weapons with iron ones.

Steel weapons, steel arrows, even steel crossbows.

Chen Hong improved the crossbow and created the repeating crossbow, making the already terrifying crossbow tactics of the Qin Dynasty even more terrifying.

Amidst a rain of arrows, a strong wind was summoned for a comprehensive, all-encompassing attack.

Even the Xiongnu, skilled with bows and arrows, feared such a barrage of fire.

Chen Hong also created iron armor, which is the iron lamellar armor of the Han Dynasty.

It is made of rectangular or square iron plates woven together.

Ordinary soldiers were supplied with simple lamellar armor.

Generals were supplied with more sophisticated lamellar armor, which had a higher production cost.

精制扎甲采用中小型甲片（高4.6~5cm，宽2.7~3.4cm），甚至更小的槐叶/柳叶形甲片（高<4cm，宽<2.5cm）。    甲片数量可达2000~3000片，防护更严密灵活。

Previously, almost all Qin soldiers wore leather armor; not a single piece of iron armor was available. Only officers could afford iron armor.

Previously, the rate of Qin soldiers wearing leather armor was about 74%, the rate of wearing helmets was about 13%, and the rate of weaponry was nearly 100%.

Weapons generally include halberds, crossbows, and swords.

Basic weapons such as spears and swords must be provided by the soldiers themselves and can be purchased from the military market.

Heavy equipment such as crossbows and arrows were supplied by the state.

Now, with Chen Hong's technical support, Daqin has begun building steel mills on various mines, and production is increasing daily.

He started to become arrogant and domineering.

The soldiers' leather armor coverage rate reached 100% (at least all of them wore leather armor).

The armor coverage rate has reached 38%, and production for replacement is still ongoing.

The weapon adoption rate is 100%, and the replacement rate of bronze weapons with iron weapons is 75%, and production and replacement are still ongoing.

The helmet rate has reached 52%, and production of helmets is still underway.

Helmets are still very important, as we all know that arrows are projectiles, and they generally fall from above.

The helmet can protect against stray arrows from above and can save lives in critical moments.

The Xiongnu, a nomadic people of the steppes, were most adept at long-range, kite-like tactics, launching arrows from horseback.

If you can win, fight; if you can't, run away.

Anyway, they have four legs, so ordinary Han Chinese infantrymen can't catch up with them.

At this point, a helmet becomes very important.

Not every soldier has the protection of a shield bearer.

Only important crossbowmen will have shield bearers to protect them.

At this critical moment, a helmet can save a life.

This is especially true for cavalrymen who have no cover.

Therefore, cavalrymen, unless they were extremely poor, would generally wear a helmet.

Seeing that his army was getting better and better equipped and stronger, Qin Shi Huang, Ying Zheng, could no longer contain himself.

They wanted to launch a northern expedition against the Xiongnu and eliminate this major threat.

Compared to the Baiyue tribes in the south who were confined to a corner of the country, the Xiongnu in the north had much greater potential.

On the vast grasslands, as long as the Xiongnu became powerful, they could easily annex many tribes and develop and merge them into a super tribal alliance, according to the law of the jungle on the grasslands.

The Xiongnu are currently restrained by the Donghu and Yuezhi tribes.

However, Emperor Qin Shi Huang had already seen the signs of the rise of the Xiongnu and was determined to suppress this emerging tribe.

To prevent them from becoming too powerful in the future and turning around to invade the agricultural peoples of the south.

Even the newly enfeoffed vassal states were eager to expand their territories and increase their land area.

Meng Tian was given command of 30 elite troops from the Great Wall Army of the Qin Dynasty, who had just been re-equipped, to lead a northern expedition against the Xiongnu!

Meng Tian led the elite troops from Guanzhong from Xianyang, forming a long marching column, towards the Great Wall in the north.

Upon reaching the Great Wall in the north, the Great Wall Legion was assembled and set out to conquer the grasslands beyond the Great Wall.

Meng Tian turned the Great Wall into an outpost and supply station for his campaigns against the northern Xiongnu.

The Great Wall, like a sleeping dragon, served as a vital lifeline, enabling the timely transmission of messages and the replenishment of supplies.

They could also use this as a base and stronghold to strike directly into the heart of the Xiongnu in the north without worrying about their food supplies being cut off.

The first war between Qin and Xiongnu officially began!

Meng Tian led his army with the principles of benevolent rule, advancing steadily and sweeping through the enemy lines.

Under the crushing force of extremely high armor coverage and iron weapons and crossbows.

In addition, the Qin army had iron discipline and a strong desire for military merit.

Their combat power is off the charts, crushing any army of this era.

The Xiongnu people, of course, could not withstand such an iron fist.

They were forced into a series of defeats.

The most amazing thing is that this battle is different.

Wherever Meng Tian conquered, he built roads with cement.

It not only ensured the supply of food and provisions, but also the speed of transportation and information transmission.

Moreover, Meng Tian brought a large number of laborers and puppeteers to build fortresses and strongholds at various strategic locations using cement.

Ensure that the influence extends to the surrounding grasslands, connecting them together and controlling all parts of the grasslands.

The First Emperor also ordered many vassal states to send troops to support Meng Tian, ​​expand their territory, and build cities in various important locations on the grasslands.

By controlling those fertile grasslands, one essentially holds the lifeline of nomadic peoples in their grasp.

The royal army set out from the Hetao Plain, which is shaped like the Chinese character "几" (ji), and advanced all the way.

(The Hetao Plain was originally the grazing land of the Xiongnu. Qin Shi Huang sent Meng Tian to conquer it during his first northern expedition against the Xiongnu and established 44 counties there. Therefore, this area is now part of the Qin Dynasty's territory. It was only recently incorporated into the Qin Dynasty's territory, and Touman Chanyu was still dead.)

The Hetao Plain, with the Yinshan Mountains serving as a natural defensive line, was a crucial strategic location. During the chaos at the end of the Qin Dynasty, it was seized by the Xiongnu, becoming the focus of the first major conflict between the Han and Xiongnu.
Meng Tian led his army across the Yin Mountains, expanding their territory and seizing the grasslands on the northern slopes of the Yin Mountains from the Xiongnu.

At this time, the grasslands on the northern slopes of the Yinshan Mountains were covered with trees and vast grasslands, making them the most fertile and important pastureland for the Xiongnu in the southern Gobi Desert.

At that time, the Xiongnu were not as powerful or as vast as the Han Dynasty.

At this time, the Xiongnu were in the early stages of their rise, and were restrained by the Hexi Corridor and the Tianshan Mountains on the left, as well as the established Yuezhi tribe.

On the right, there was also the old and declining Donghu tribe keeping them in check.

The fertile Hetao Plain, known as the "Jiangnan of the North," was once again seized by the newly established Qin Empire.

Therefore, the last fertile grassland south of the Gobi Desert for the Xiongnu was the grassland on the northern foothills of the Yin Mountains.

As a result, even this last piece of grassland could not be saved.

(End of this chapter)